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Oxides of elements - class-XII

Description: oxides of elements
Number of Questions: 93
Created by:
Tags: p-block elements chemistry of non-metals the p-block elements chemistry
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Which of the following are basic oxides? 
$Mn _2O _7$ ,
$V _2O _3$, $V _2O _5$, $Cr _2O _3, CrO$ 

  1. $Mn _2O _7$ and $V _2O _3$

  2. $V _2O _3$ and $CrO$

  3. $CrO$ and $Cr _2O _3$

  4. $V _2O _5$ and $V _2O _3$


Correct Option: B
Explanation:

As metallic character decreases as we move across the period then basicity of oxides increases.

Also, we know oxide in lowest oxidation state of element is more basic. So, in $V _2O _3$ and $CrO$, oxidation state of $V$ and $Cr$ are $+3$ and $+2$ respectively which is lowest among others.

Select the correct option regarding the properties of dioxygen?

  1. Dioxygen never reacts with metals.

  2. Dioxygen is diamagnetic in nature.

  3. Combination of dioxygen with other elements is highly exothermic process.

  4. Dioxygen liquefies at 55 K and freezes at 90 K.


Correct Option: C
Explanation:

Dioxygen reacts with metals and is paramagnetic. It combines with other elements to form oxides where the reaction is highly exothermic.

Which one of the following is an amphoteric oxide?

  1. $Na _2O$

  2. $SO _2$

  3. $B _2O _3$

  4. $ZnO$


Correct Option: D
Explanation:

$ZnO$ is an amphoteric oxide. It reacts with both acid and base to produce respective salts. 

A group of acidic oxide is:

  1. $CrO _{3},Mn _{2}O _{7}$

  2. $ZnO,Al _{2}O _{3}$

  3. $CaO,ZnO$

  4. $Na _{2}O,Al _{2}O _{3}$


Correct Option: A
Explanation:

here,${ CrO } _{ 3 }$ are acidic oxides

${ CrO } _{ 3 }+{ H } _{ 2 }O\longrightarrow { H } _{ 2 }{ CrO } _{ 4 }\ { Mn } _{ 2 }{ O } _{ 7 }+{ H } _{ 2 }O\longrightarrow { 2HMnO } _{ 4 }$

Which is most basic oxide of chromium ?

  1. $ CrO $

  2. $ CrO _2 $

  3. $ CrO _3 $

  4. $ Cr _2O _3 $


Correct Option: A

Which of the following oxide can be converted to metal easily ?

  1. ZnO

  2. HgO

  3. PbO

  4. $C{u _2}O$


Correct Option: B

$ZnO+2HCl\longrightarrow  X+{H} _{2}O$
$ZnO+2NaOH\longrightarrow  Y+{H} _{2}O$
Identify $X,Y$ and the nature of $ZnO$ best described by the above reaction

  1. $X=Zn{Cl} _{2}$; $Y=NaZn{O} _{2}$; Nature of $ZnO$- Amphoteric

  2. $X=Zn{Cl} _{2}$; $Y={Na} _{2}Zn{O} _{2}$; Nature of $ZnO$- Amphoteric

  3. $X=Zn{Cl} _{2}$; $Y=NaZn{O} _{2}$; Nature of $ZnO$- Acidic

  4. $X=Zn{Cl} _{3}$; $Y=Zn{OH} _{2}$; Nature of $ZnO$- Basic


Correct Option: B

Which IS BASIC OXIDE

  1. $Tl _{2}O _{3}$

  2. $B _{2}O _3$

  3. $Ga _{2}O$

  4. $InO$


Correct Option: A
Explanation:

As metal oxides are basic and Tl2O3 makes salt and water after reacting with acid. 

An oxide which forms salts when it reacts with both acids and alkali is :

  1. acidic oxide

  2. basic oxide

  3. amphoteric oxide

  4. none of the above


Correct Option: C
Explanation:

An oxide which forms salts when it reacts with both acids and alkali is knwn as amphoteric oxides. $e.g.$ $Al _2O _3$.

Which of the following is an amphoteric oxide?

  1. $ MgO $

  2. $ Al _2O _3 $

  3. $ SO _2 $

  4. $ P _2O _5 $


Correct Option: B

Non-metals combine with oxygen to form usually:

  1. basic oxides

  2. neutral oxides

  3. acidic oxides

  4. amphoteric oxides


Correct Option: C
Explanation:

non-metal oxides forms acid after diluting in water Eg. $\mathrm{H} _{2}C{O} _{3}, {H} _{2}S{O} _{4}$
$\therefore$   non metals combine with oxygen to from usually acidic oxcides because of its low electronegativity 

Which one of the following is an amphoteric
oxide?

  1. $Na _{2}O$

  2. $SO _{2}$

  3. $B _{2}O _{3}$

  4. $\mathrm{Z}\mathrm{n}\mathrm{O}$


Correct Option: D
Explanation:


$\mathrm Na _{2}O $ and first group oxides are basic while non-metal oxides such as $\mathrm SO _{2}$ and $B _{2}O _{3} $ are acidic.
ZnO is amphoteric because it can reacts with acid as well as base to produce salt and $\mathrm H _{2}O$.

Which of the following is not a normal oxide?

  1. $\mathrm{N}\mathrm{a} _{2}\mathrm{O}$

  2. $\mathrm{Al} _{2}\mathrm{O} _{3}$

  3. $\mathrm{K}\mathrm{O} _{2}$

  4. $\ \mathrm{M}\mathrm{g}\mathrm{O}$


Correct Option: C
Explanation:

$KO _2 \rightarrow K^+ O _2^-$
Hence, $KO _2$ is a super oxide with $O _2^-$ ion.
$Na _2O, Al _2O _3, M _gO$ are normal oxides with $O^{2-}$ ion.

Which of the following elements forms amphoteric oxides?

  1. Beryllium

  2. Aluminium

  3. Zinc

  4. All


Correct Option: D
Explanation:

An amphoteric species is a molecule or ion that can react as an acid as well as base. The word amphoteric means both. Many metals such as copper, zinc, tin, lead, aluminium and beryllium form amphoteric oxides or hydroxides.

Metal oxide which show basic as well as acidic behaviour are known as:

  1. neutral oxide

  2. amphoteric oxide

  3. metalloid oxide

  4. none of the above


Correct Option: B
Explanation:

Metal oxides which shows basic as well as acidic behaviour as known as amphoteric oxides. Thus aluminium metal and zinc metal form amphoteric oxides.

Which of the following oxide is thermally least stable?

  1. $CaO$

  2. $Al _2O _3$

  3. $Fe _2O _3$

  4. $Ag _2O$


Correct Option: A
Explanation:

The melting points and thermal stability of the oxides are determined by the nature of the distribution of valent electrons from the components over localized and nonlocalized ones and by the probability of the formation of stable electron configurations of transition metal and oxygen atoms. The drop in statistical weight of stable configurations and increase in proportion of nonlocalized electrons results in a drop in melting point and thermal stability of the oxides.

Calcium oxide is thermally least stable as it reacts exothermically with water producing hydroxide.
$CaO +H _2O \rightleftharpoons Ca(OH) _2$

Match the following, regarding nature of the oxides.

Column -I Column-II
a. $N _2O$ (i) Basic
b. BaO (ii) Amphoteric
c. $As _2O _3$ (iii) Acidic
d. $Cl _2O _7$ (iv) Neutral
  1. a(ii), b(i), c(iii), d(iv)

  2. a(iv), b(i), c(iii), d(ii)

  3. a(iv), b(i), c(ii), d(iii)

  4. a(ii), b(i), c(iv), d(iii)


Correct Option: C
Explanation:

(A) $N _2O\longrightarrow$ (iv) Neutral as it neither shows properties of a base nor acid.

(B) $BaO\longrightarrow$ (i) Basic; Metallic oxides are basic oxides.
(C) $As _2O _3\longrightarrow$ (ii) Amphoteric as it can act both as a base and an acid.
(D) $Cl _2O _7\longrightarrow$ (iii) Acidic as non-metallic oxides are acidic in nature.

Which of the following oxide is most acidic ?

  1. $P _2O _5$

  2. $N _2O _5$

  3. $Sb _2O _5$

  4. $As _2O _6$


Correct Option: B
Explanation:

$N _2O _5$ is the most acidic as it is having $+5$ oxidation state with highest electronegativity of $N$.

A light metal M is a good conductor of electricity. It forms a layer when exposed to air, which is an amphoteric oxide of the formula $M _2O _3$. Identify M.

  1. Ca

  2. Al

  3. Mg

  4. Ba


Correct Option: B
Explanation:

Here, only $Al$ forms amphoteric oxide of formula $Al _2O _3$.

It forms protective layer of $Al _2O _3$ when exposed to air.

$Na _2O$, $MgO$, $Al _2O _3$ and $SiO _2$ have heat of formation equal to $-416,\ -602,\ -1676$ and $-911$ $ kJ mol^{-1}$ respectively. The most stable oxide is:

  1. $Na _2O$

  2. $MgO$

  3. $Al _2O _3$

  4. $SiO _2$


Correct Option: B
Explanation:
$(B)$ A smaller higher charged ion will be closer to the oxide ions $(O^{2-})$, which means the thermal stability of $MgO$ is more or it takes more energy to break the crystal structure of $MgO$

Which one of the following oxides in neutral?

  1. $SiO _7$

  2. $SnO _2$

  3. $ZnO$

  4. $CO$


Correct Option: B
Explanation:

The correct answer is $(B),SnO _2$ 

Because its react with acids as well as with bases to form corresponding salt,
$Sn{O _2} + 2{H _2}S{O _4}\left( {conc.} \right) \to Sn{\left( {S{O _4}} \right) _2} + 2{H _2}O$
and $Sn{\left( {S{O _4}} \right) _2} + 2NaOH \to N{a _2}Sn{O _3} + {H _2}O$ 

Acidic oxides react with water to give ________.

  1. base

  2. acids

  3. salt

  4. none of these


Correct Option: B
Explanation:
Acids are formed by reacting acidic oxides with water. $CO _2$ is acidic oxide. On reacting it with water, $H _2CO _3$, which is an acid forms.
$CO _2 + H _2O \rightarrow H _2CO _3$
                                 $acid$

Two oxides of a metal contain 27.6% and 30.0% of oxygen, respectively. If the formula of the first oxide be ${ { M } _{ 3 }O } _{ 4 }$, find that of the second oxide.

  1. $MO _3$

  2. $M _2O$

  3. $M _2O _3$

  4. $MO$


Correct Option: C
Explanation:
Given that, formula of first oxide$ = M _3O _4$
Let mass of the metal = x
% of metal in $M _3O _4$ $=\dfrac{3x}{3x+64}\times100$
But  as given % age $= (100-27.6) = 72.4 $%
so, $\dfrac{3x}{3x+64}\times100$ = 72.4
or $x = 56$.
In 2nd oxide,
Given, oxygen = 30%, So metal = 70%
So, the ratio is
$M : O$=$\dfrac{70}{56 }:\dfrac{ 30}{16}$
$\implies 1.25 : 1.875$
$\implies 2 : 3$
So, 2nd oxide is $M _2O _3$

The binary compounds of metallic or non-metallic elements with oxygen are called ________.

  1. oxoacid

  2. oxide

  3. oxo

  4. none of these


Correct Option: B
Explanation:

The binary compound of elements with oxygen is called oxides. Here oxygen is anionic part. So suffix is 'ide'.

Example: Carbon dioxide $CO _2$

Oxides which show both acidic and basic nature are called as ______ oxides.

  1. dual

  2. amphoteric

  3. aprotic

  4. none of these


Correct Option: B
Explanation:

Amphoteric oxides show acidic and basic nature. They react with both acids and bases. 

$Al _2O _3$ is an example of amphoteric oxide.

Among the second period which group element form most acidic oxide.

  1. $17^{th}$ group

  2. $14^{th}$ group

  3. $15^{th}$ group

  4. $16^{th}$ group


Correct Option: A
Explanation:

Group element having high electronegativity will be most acidic.

And we know group 17 elements are highly electronegative.

A metal $X$ when burnt in air, $X$-forms oxide and nitride both. $X$ can be:

  1. $Rb$

  2. $Mg$

  3. $Na$

  4. $K$


Correct Option: B
Explanation:

$Mg$ forms oxide as well as nitride.

$Mg+O _2+N _2\longrightarrow MgO+{Mg} _3N _2$

A metal forms two oxides. The higher oxide contains $80\%$ metal. $0.72 g$ of the lower oxide gave $0.8 g$ of higher oxide when oxidized. Then the ratio of the weight of oxygen that combines with the fixed weight of the metal in the two oxides will be:

  1. $2 :3$

  2. $2: 1$

  3. $4 :5$

  4. $3 : 2$


Correct Option: B
Explanation:
Given that ,in higher oxide 80% metal is true.
wt. of metal$=\dfrac { 80 }{ 100 } \times 0.8\\$       
                    $ =0.64gm\\ $
wt. of oxygen$=0.16gm$
in lower oxide,
wt. of metal will be same as that of higher oxidation state(+2)

wt. of oxygen$=(72-0.64)=0.08g$

so,ratio of weight of $O _2$ & meals in two oxide is $0.16:0.08=2:1$.
1000ml of 0.75 M HCl = 0.75 mol

So, 25 ml of HCl will contain HCl = $0.75 \times 25 /1000$  = 0.01875

2 mol of HCl reacts with 1 mol of $CaCO _3$

So, 0.01875 mol of HCl will react with $\frac{1}{2}$ $\times$ 0.01875  = $0.009375$ mol

Molar mass of $CaCO _3$ = 100 g

Hence, the mass of 0.009375 mol of $CaCO _3$  = no. of moles $\times $ molar mass$
                                                                          
 $0.009375$ $\times100$  
                                                                   
Hence, the correct option is $C$.

Metal X form 2 oxide. Formula of ${ 1 }^{ st }$ is ${ XO } _{ 2 }$ ${ 1 }^{ st }$ oxide contain $50\% { O } _{ 2 }$. If ${ 2 }^{ nd }$ oxide contain $60\% { O } _{ 2 }$ .Formula of ${ 2 }^{ nd }$ oxide?

  1. ${ X } _{ 2 }O$

  2. ${ XO } _{ 3 }$

  3. ${ X } _{ 2 }{ O } _{ 3 }$

  4. ${ X } _{ 3 }{ O } _{ 2 }$


Correct Option: C
Explanation:

Given that in${ XO } _{ 2 },50%$% of $O _2$ is present

${ 2 }O _{ 2 }=32\ \frac { 32 }{ M+32 } =0.5$
now ,given that is second oxide 60% of   is present let no. of metal X contained in this oxide.is n then,
$\cfrac { 32 }{ n\times 32+32 } =0.6\ \cfrac { 1 }{ n+1 } =0.6\ 1=0.6n+0.6\ n=\cfrac { 0.4 }{ 0.6 } =\cfrac { 2 }{ 3 } \ { X } _{ 2 }{ O } _{ 3 }$  
is formula of compound

$K0 {2}$(potassium super oxide) is used in oxygen cylinder in space and submarines. This is because it ____________.

  1. absords $CO _{2}$ and increase $O _{2}$ content

  2. eliminates moisture

  3. absords $CO _{2}$

  4. produces ozone


Correct Option: A
Explanation:

Because it absorbs $CO _2$ and increases $O _2$ concentration according to the following reaction

$4K{ O } _{ 2 }+2{ CO } _{ 2 }\rightarrow 2{ K } _{ 2 }{ CO } _{ 3 }+3{ O } _{ 2 }$

$Pb{O} _{2}$ oxide is:

  1. basic

  2. acidic

  3. neutral

  4. amphoteric


Correct Option: D
Explanation:

The $Pb{ O } _{ 2 }$ behaves as acidic and basic property so it is called as amphoteric.

When $Pb{ O } _{ 2 }$ dissolved in a strong base $Pb{ O }{ H } _{ 6 }$ is obtained so it is an acidic property.
when $Pb{ O } _{ 2 }$ dissolved in HCl,$PbCl _{ 6 }$ is formed so it is a basic property.
Thus $PbO _{ 2 }$ behaves as amphoteric in nature.

Two oxides of a metal contain $50$% and $40$% metal (M) respectively. If the formula of first oxide is $MO _2$, the formula of second oxide will be:

  1. $MO _2$

  2. $MO _3$

  3. $M _2O$

  4. $M _2O _5$


Correct Option: B
Explanation:
$\text{Compound } 1\quad\quad\quad\quad 50\% M+50\% O$
$\text{formula}\quad\quad\quad\quad MO _2$
Let atomic weight of metal be $X,$
$\Longrightarrow MO _2:$    $\cfrac{16}{X}=\cfrac{1}{2}$
Hence atomic weight of metal $=32$
$\text{Compound }2:$ $40\% M=\cfrac{40}{32}=1.25=1\\60\%O=\cfrac{60}{16}=3.75=3$
$\therefore$ Formula is $MO _3$.

Which of the following oxide is an amphoteric oxide?

  1. $Bi _{2}O _{3}$

  2. $N _{2}O _{3}$

  3. $P _{4}O _{10}$

  4. $Sb _{2}O _{3}$


Correct Option: D
Explanation:
Those metal oxides which show basic as well as acidic behavior are known as amphoteric oxide
Here ${ Sb } _{ 2 }{ O } _{ 3 }$ oxide is an amphoteric oxide.

Two metallic oxides contain $27.6$% and $30$% oxygen respectively. If the formula of the first oxide is ${X} _{3}{O} _{4}$, that of the second will be ?

  1. $XO$

  2. $X{O} _{2}$

  3. ${X} _{2}{O} _{5}$

  4. ${X} _{2}{O} _{3}$


Correct Option: D
Explanation:

Solution:

Given that, formula of first oxide = $\\ { M } _{ 3 }{ O } _{ 4 }$

Let mass of the metal = x


% of metal in  $M _{ 3 }O _{ 4 }$ $=\dfrac { 3x }{ 3x+64 } \times 100$


but as given percentage$ =(100-27.6) = 72.4 %$ $\left( \dfrac { 3x }{ 3x+64 }  \right) \times 100=72.4$ or $x=56$


in 2nd oxide

$oxygen$ $=30%$

so for the metal $=70%$


so the ratio is,


$M:O=\dfrac { 70 }{ 56 } :\dfrac { 30 }{ 161.25 } :1.8752:3$ 


 so the second oxide is,


${ M } _{ 2 }{ O } _{ 3 }$


Hence the answer is

${ M } _{ 2 }{ O } _{ 3 }$.(${ X } _{ 2 }{ O } _{ 3 }$)

Two oxides of a metal contain 72.4% and 70% of metal respectively? If formula of 2nd oxide is $ M _{2}O _{3} $, find that of the first ?

  1. MO

  2. $ M _{3}O _{4} $

  3. $ M _{3}O _{2} $

  4. $ MO _{2} $


Correct Option: B

Which of the following is the most acidic?

  1. ${ P } _{ 2 }{ O } _{ 5}$

  2. ${ N } _{ 2 }{ O } _{ 5 }$

  3. ${ Sb } _{ 2 }{ O } _{ 5 }$

  4. ${ As } _{ 2 }{ O } _{ 5 }$


Correct Option: B
Explanation:

As the electronegativity value of the element increases. the acidic character of the oxide also increases.

Here among $N,P,SI$ and $As$ the most electronegative is $N$.

Thus the most acidic is $N _2O _5$.

The most acidic oxide among the following is:

  1. $Cl _2O _5$

  2. $Cl _2O$

  3. $Cl _2O _3$

  4. $Cl _2O _7$


Correct Option: D
Explanation:

$Cl _2O _7$ is most acidic because on reacting with water , it gives  most strongest acid than the other three i.e., $HClO _4$ .

So, $Cl _2O _4$ is most acidic 

Which of the following statements are not correct ?

  1. All C - O bonds in $CO _3^{2-}$ are equal but not in $H _2CO _3$

  2. All C - O bonds in $HCO _2^-$ are equal but not in $HCO _2H$.

  3. C - O bond length in $HCO _2^-$ is longer than C - O bond length in $CO _3^{2-}$

  4. C - O bond length in $HCO _2^-$ and C - O bond length in $CO _3^{2-}$ are equal


Correct Option: C

The type of ions responsible for scum formation are:

  1. oxides

  2. hydroxides

  3. chlorides

  4. carbonates


Correct Option: A
Explanation:

The scum is formed when soap is used in hard water and hard water consists of carbonate. For this process $Oxides$ ions responsible for scum formation.

Hence,
The option $(A)$ is correct.

Which of the following oxide is least basic?

  1. $CrO$

  2. $Cr _2O _3$

  3. $CrO _3$

  4. $Cr _2O _4$


Correct Option: A

An oxide of element $A$ was analysed and found to have mass ratio of $A$ to oxygen equal to $7:3$. Then formula of oxidation can be :

  1. $A _{3}O _{2}$

  2. $A _{2}O _{3}$

  3. $AO$

  4. $A _{2}O$


Correct Option: B

Titanium oxide $(TiO _{2})$ is heated in stream of hydrogen gas to give water and a new oxide $Ti _{x}O _{y}$. If $1.6\ gm$ of  $TiO _{2}$ produces $1.44\ gm$ of $Ti _{x}O _{y}$, the formula of new oxide is
[Atomic weight of $Ti=48$]:

  1. $TiO$

  2. $Ti _{2}O _{3}$

  3. $Ti _{2}O _{5}$

  4. $None\ of\ these$


Correct Option: A

The pair of amphoteric oxides is: 

  1. $VO,\,C{r _2}{O _3}$

  2. ${V _2}{O _5},\,C{r _2}{O _3}$

  3. $V{O _2},\,C{r _2}{O _3}$

  4. ${V _2}{O _5},\,Cr{O _3}$


Correct Option: B
Explanation:
An amphoteric compound is a molecule or ion that can react both as an acid and as a base. Many metals (such as copper, zinc, tin, lead, aluminium, and beryllium) form amphoteric oxides or hydroxides. 

Amphoterism depends on the oxidation states of the oxide. Al2O3 is an example of an amphoteric oxide.

 V2O5 and Cr2O3 are amphoteric oxides because both react with alkalies as well as acids.

So, option B is correct

Which of the following oxide is most acidic? 

  1. $Na _2O$

  2. $MgO$

  3. $SiO _2$

  4. $Cl _2O _7$


Correct Option: D
Explanation:

$Na _2O$ , MgO are basic oxides.

$Cl _2O _7$  has highest acidity because it is an oxide of non metal .
Non metallic oxides are acidic 
This oxide reacts with water to give $HClO _4$ i,e,. strong acid.
So, 

Which of the following shows the tendency to from peroxide?

  1. Lithium

  2. Magnesium

  3. Berylium

  4. Radium


Correct Option: A

Which of the following oxides is neutral?

  1. $CO$

  2. $SnO _2$

  3. $ZnO$

  4. $SO _2$


Correct Option: B

The order in which the following oxides are arranged to decreasing basic nature is $Al _2O _3$<$MgO$<$CuO$<$Na _2O$

  1. True

  2. False


Correct Option: A
Explanation:

Oxides can be called as binary compounds formed by the reaction of oxygen with other elements.  Oxides are classified as acidic, basic, amphoteric or neutral.  An oxide is a compound that contains at least one oxygen atom and one other element in its chemical formula.  Oxide is a dianion of oxygen.  Examples of oxides are CaO, BaO, ZnO etc.

Na2O, MgO, Al2O3, CuO is the decreasing order of basic nature.

An element $X$ which occurs in the second period has an outer electronic structure $s^{2}p^{2}$. The formula and acid-base character of its oxide, respectively are,

  1. $XO _{3}$, basic

  2. $X _{2}O _{3}$, basic

  3. $X _{2}O _{3}$, amphoteric

  4. $XO _{2}$, acidic


Correct Option: D
Explanation:
The outer electronic configuration given is $ns^2np^2$. It is the configuration of the Carbon family. So we know that non-metal oxides are acidic and have general formula $XO _2$.
Option D is correct.

The correct increasing order of acidic strength for the following oxides ${P} _{2}{O} _{3},{N} _{2}{O} _{3},{SO} _{3}$ is

  1. ${P} _{2}{O} _{5}< {N} _{2}{O} _{5}< {SO} _{3}$

  2. ${P} _{2}{O} _{5}< {SO} _{3}< {N} _{2}{O} _{5}$

  3. $ {SO} _{3}< {P} _{2}{O} _{5}< {N} _{2}{O} _{5}$

  4. ${N} _{2}{O} _{5}< {P} _{2}{O} _{5}< {SO} _{3}$


Correct Option: A

Which of the oxide gives two oxyacid in water ?

  1. ${N _2}{O _3}$

  2. $NO$

  3. $N{O _2}$

  4. ${P _4}{O _{10}}$


Correct Option: B
Explanation:

Oxyacid, any oxygen-containing acid. Most covalent nonmetallic oxides react with water to form acidic oxides; that is, they react with water to form oxyacids that yield hydronium ions (H3O+) in solution. There are some exceptions, such as carbon dioxide, CO, nitrous oxide, N2O, and nitric oxide, NO.

Most basic oxide among the following is ?

  1. ${{\text{P}} _{\text{2}}}{{\text{O}} _{\text{5}}}$

  2. ${\text{SnO}}$

  3. ${{\text{B}} _{\text{2}}}{{\text{O}} _{\text{3}}}$

  4. ${\text{MgO}}$


Correct Option: C

Which one of the following is normal oxide?

  1. $K{O _2}$

  2. $Ba{O _2}$

  3. $Si{O _2}$

  4. $Cs{O _2}$


Correct Option: C

${PbO _2}$ is :

  1. acidic.

  2. basic.

  3. reducing agent.

  4. oxidizing agent.


Correct Option: A,B,D
Explanation:

$PbO _2$ is amphoteric so it can act as acid as well as base. Also it is strong oxidising agent.

Which of the following oxides is/are neutral?

  1. ${N _2 O}$

  2. $CO$

  3. ${Al _2 O _3}$

  4. $NO$


Correct Option: A,B,D
Explanation:

$Al _2O _3$ is amphoteric oxide, apart from this all other are neutral oxides.

Which of the following is/are peroxide(s) ?

  1. $ PbO _{2} $

  2. $ H _{2}O _{2} $

  3. $ SrO _{2} $

  4. $ BaO _{2} $


Correct Option: B,C,D
Explanation:

In $ {PbO} _{2}, $ Its $ Pb^{+4}$ & $ 2O^{-2} $


In $ {H _{2}O} _{2},$ there is peroxide linkage

$ H-O-O-H $ 

In $ SrO _{2}, $ as Sr is alkaline earth metal 
$ \therefore $ Its $ Sr^{2+} $

$ \therefore $ Its $ O _{2}^{-2}, (\bar{O}-\bar{O}) $ peroxide linkage 

In $ BaO _{2},$ Its $ Ba^{{+2}}\therefore O _{2}^{-2} $

$ \bar{O}-\bar{O} $ peroxide linkage 

Hence, the correct options are $\text{B}$, $\text{C}$ and $\text{D}$

Which of the following oxides is amphoteric in character?

  1. $CaO$

  2. $CO _2$

  3. $SiO _2$

  4. $SnO _2$


Correct Option: D
Explanation:
Option (D) is correct.
$SnO _2$ is amphoteric in character.
$SnO _2 + 2NaOH \rightarrow Na _2SnO _3 + H _2O$
$SnO _2 + 4HCl \rightarrow SnCl _4 + 2H _2O$+$CO _2$ is acidic in character.
$SiO _2$ is very weak acid.
$CaO _2$ is basic in nature.

A metal oxide is acidic when :

  1. $\sqrt{\varphi}\, <\, 2.1$

  2. $\sqrt{\varphi}\, =\, 2.1\, to\, 3.2$

  3. $\sqrt{\varphi}\, >\, 3.2$

  4. None of these


Correct Option: C
Explanation:

A metal oxide is acidic when $\sqrt{\varphi}\, >\, 3.2$

Which of the following oxides is/are not amphoteric in character?

  1. CaO

  2. $CO _2$

  3. $SiO _2$

  4. $SnO _2$


Correct Option: A,B,C
Explanation:

$CaO$, $CO _2$ and $SiO _2$ when dissolved in water gives base ,hence they are basic oxides.


$SnO _2$ do not react with water, so it is amphoteric. 

Hence options A,B, & C are correct.

Which of the following oxides are not neutral?

  1. $CO$

  2. $SnO _2$

  3. $ZnO$

  4. $SiO _2$


Correct Option: B,C,D
Explanation:

 $CO$ is a neutral oxide insoluble in water, but behaves as amphoteric compound. 


$SiO _2$ amphoteric oxide, $SnO _2$ basic oxide and  $ZnO$  is amphoteric oxide.

Hence options B,C & D are correct.

Select the correct statements:

  1. s-block metal oxides are basic in nature, except $BeO$ which is amphoteric.

  2. p-block metal oxides are acidic in nature, except $NO$,$ N _2O$,$ CO$.

  3. d-block metal oxides are basic, acidic, and amphoteric in nature.

  4. d-block metal oxides are only basic in nature.


Correct Option: A,B,C
Explanation:

(A) BeO is amphoteric in nature. It reacts with acids as well as alkalies.  Oxides of other s block metal elements are basic in nature. They react only with acids. hence, the option A is correct.

(B) The oxides $NO, N _2O,CO$   are neutral. Whereas the  remaining oxides of p block metals are acidic in nature. Thus, the option B is correct.

Some of the d block metal oxides are basic in nature, some of them acidic in nature where as the rest are amphoteric in nature. Thus, the option C is correct and option D is incorrect.

The species that do not contain peroxide ions is :

  1. $PbO _2$

  2. $H _2O _2$

  3. $SrO _2$

  4. $BaO _2$


Correct Option: A
Explanation:

Only true peroxides which have -O-O- bond give hydrogen peroxide with dilute acids.
$PbO _2$ does not give hydrogen peroxide with dilute acids. So it is not a true peroxide.

Hence option A is correct.

Which one of the following statement is true?

  1. According to the modern atomic theory, atoms of the same element may have different atomic weights

  2. Reduction is the process of electron loss

  3. Acidic oxide are the non-metallic oxides

  4. The solubility of all substances decreases with increase in temperature


Correct Option: C
Explanation:

Acidic oxides are the oxides which reacts with water to form an acid. Acidic are non- metallic oxides. Some of the examples are ${ SO } _{ 3 }$ forms sulphuric acid and ${ CO } _{ 2 }$ forms carbonic acid. 

So, correct answer is option C.

Which choice or choices demonstrate amphoterism?
i. $HCl + H _{2}O \rightarrow H _{3}O^{+} + Cl^{-}$ and $H _{2}O + N _{3} \rightarrow OH^{-} + NH _{4}^{-}$
ii. $HS^{-} + HCl \rightarrow Cl^{-} + H _{2}S$ and $HS^{-} + NH _{3} \rightarrow NH _{4}^{+} + S^{2-}$
iii. $HCl + NaOH \rightarrow NaCl + H _{2}O$ and $NaCl + H _{2}O \rightarrow HCl + NaOH$

  1. i only

  2. ii only

  3. iii only

  4. i and ii only

  5. i and iii only


Correct Option: D
Explanation:

Amphoteric compound or ion is a molecule that cn act as both acid as well as base.

In the first reaction, $H _2O$ acts as both acid and base.It accepts proton and loses proton. Hence. it shows amphoterism.
In the second reaction, ${ HS }^{ - }$ does the same thing.
It accepts and loses proton. 
Hence, both shows amphoterism.

Which one among the following can be classified as amphoteric?

  1. $Na _3PO _4$

  2. HCl

  3. NaOH

  4. $HSO^- _4$

  5. $C _2O^{2-} _4$


Correct Option: D
Explanation:

$\displaystyle HSO^- _4$ can be classified as amphoteric. It can donate a proton and act as an acid. At the same time, it can accept a proton and act as a base.
$\displaystyle HSO^- _4 \rightarrow H^+ + SO _4^{2-}$
$\displaystyle HSO^- _4 + H^+ \rightarrow H _2SO _4$

Amphoteric species is:
  1. $Na _3PO _4$

  2. $HSO _4^-$

  3. $KOH$

  4. $HNO _3$

  5. $C _2O^{2-} _4$


Correct Option: B
Explanation:

Amphoteric specie is $\displaystyle HSO _4^-$.
It reacts with acid as well as base.
$\displaystyle HSO _4^- + H^+ \rightarrow H _2SO _4$
$\displaystyle HSO _4^-+ OH^- \rightarrow SO _4^{2-} + H _2O$

Which of the following is not a neutral oxide?

  1. $CO$

  2. $N _2O$

  3. $H _2O$

  4. $SO _2$


Correct Option: D
Explanation:

Sodium sulphite is formed by passing sulphur dioxide gas through the solution of sodium hydroxide because sulphur dioxide is an acidic oxide.

Which of the following is a neutral oxide?

  1. $NO$

  2. $NO _2$

  3. $N _2O _3$

  4. $N _2O _5$


Correct Option: A

Which of the following constitutes a set amphoteric species.?

  1. $H _3O^+, H _2PO^- _4, HCO^- _3$

  2. $H _2O, HPO^{2-} _4, H _2PO^- _2$

  3. $H _2O, H _2PO^- _3, HPO^{2-} _4$

  4. $HC _2O^- _4, H _2PO^- _4, SO^{2-} _4$


Correct Option: C

Which of the following oxides is nuetral?

  1. CO

  2. $SnO _2$

  3. ZnO

  4. $SiO _2$


Correct Option: A
Explanation:
  • Neutral oxides show neither basic nor acidic properties and hence do not form salts when reacted with acids or bases.
  • Carbon and oxygen together have a total of 10 valence electrons in carbon monoxide. To satisfy the octet rule for the carbon, the two atoms form a triple bond, with six shared electrons in three bonding molecular orbitals, rather than the usual double bond found in organic carbonyl compounds. Since four of the shared electrons come from the oxygen atom and only two from carbon, one bonding orbital is occupied by two electrons from oxygen, forming a dative or dipolar bond. This causes a $C\leftarrow O$ polarization of the molecule, with a small negative charge on carbon and a small positive charge on oxygen. Overall the molecule is neutral.
  • Hence option A is correct answer.

Which one of the following is an amphoteric oxide?



  1. $MnO _{2}$

  2. $ZnO$

  3. $CaO$

  4. $CO _{2}$


Correct Option: B
Explanation:

ZnO is amphoteric because it can act with acid as well as base.
$ZnO + NaOH \rightarrow Na _2ZnO _2$
$ZnO+HCl \rightarrow ZnCl _2$

Which one of these is basic?

  1. $ CO _2 $

  2. $ SnO _2$

  3. $ NO _2 $

  4. $ SO _2 $


Correct Option: B
Explanation:
All others are nonmetals oxide they are all acidic oxides.

And Sn is an amphoteric both basic and acidic oxide.

Option B is correct.

(1) $N _2 + 2O _2 \leftrightarrow 2NO _2; K _e = 2 \times 10^{-31}$
(2)  $2NO ^+  \leftrightarrow N _2 + O _2;K _e = 2.2 \times 10^{-31}$
(3)  $2N _2O _5 \leftrightarrow 2N _2 + 5O _2 ; K _e = 3.8 \times 10^{-32}$
(4)  $2N _2 + O _2 \leftrightarrow 2N _2O ; K _e = 4 \times 10^{-32}$
From the above data, the most stable oxide is:

  1. $NO _2$

  2. $NO$

  3. $N _2O _5$

  4. $N _2O$


Correct Option: C
Explanation:

Most stable oxide is that whose  formation const, $K _f$ is largest 

$(1)\ N _2 + 2O _2 \leftrightarrow 2NO _2 $   $K _e = 2 \times 10^{-31}$
                                          $K _f = \sqrt{K _e}$  {$\because$ one mole $NO _2$ must be formed}
                                                $= \sqrt{0.2} \times 10^{-15}$
                                                $\approx 0.44 \times 10^{-15}$
$(2)\ 2NO^+ \leftrightarrow N _2 + O _2 $   $K _e = 2.2 \times 10^{-31}$
                                          $K _f = \dfrac{1}{\sqrt{K _e}} = \dfrac{10^{15}}{\sqrt{0.22}}$
                                                 $\approx 0.13 \times 10^{15}$
$(3)\ 2N _2 O _5 \leftrightarrow 2N _2 + 5O _2$     $K _e = 3.8 \times 10^{-32}$
                                                $K _f = \dfrac{1}{\sqrt{K _e}} \approx 0.512 \times 10^{16}$
$(4)\ 2N _2 + O _2 \leftrightarrow 2N _2O $   $K _e = 4 \times 10^{-32}$
                                          $K _f = \sqrt{K _e} = 2 \times 10^{-16}$
$\therefore N _2O _5$ is most stable.

Which of the following oxides is amphoteric in character?

  1. $CaO$

  2. $CO _2$

  3. $SiO _2$

  4. $SnO _2$


Correct Option: D
Explanation:

$SnO _2$ shows both acidic and basic properties $\therefore$ it is amphoteric in nature.

Which of the following metals produces acidic oxide ?

  1. $Fe$

  2. $Cu$

  3. $Mn$

  4. $N$


Correct Option: C
Explanation:

Mn forms acidic oxide $MN _2O _7$ and it is a transtition metal.

$MN _2O _7+H _2O\longrightarrow 2HMNO _4$

Among :   


$a) Na {2}O  \quad  b)MgO \quad c)Al _{2}O _{3}\quad  d)P _{2}O _{5}\quad  e)Cl _{2}O _{7} \quad $  

the most basic, most acidic and amphoteric oxide can be _______.

  1. a,b,c

  2. b,e,c

  3. a,e,c

  4. e,c,a


Correct Option: C
Explanation:

Metal being electropositive in nature form basic oxide .non metals being electronegative in nature from acidic oxides .


so the extent of acidity and basicity in oxide depends on electropositive and electronegative nature of elements.


most basic oxide: $Na _2O$
most acidic oxide $Cl _2O _7$
amphoteric oxide: $Al _2O _3$

Which of the following is not amphoteric ?

  1. $HS{O _4}$

  2. ${H _2}P{O _2}$

  3. ${H _2}O$

  4. non of these


Correct Option: D

Which of the following are amphiprotic in nature?

  1. $OH^-$

  2. $H _2PO^- _2$

  3. $HSO _3^-$

  4. $HF$


Correct Option: C

Which of the following oxide having ${{\text{O}} _{\text{2}}}^{{\text{ - 2}}}\,\,\,$

  1. ${\text{Na}}{{\text{O}} _{\text{2}}}\,\,\,$

  2. ${\text{Ba}}{{\text{O}} _{\text{2}}}\,\,\,$

  3. ${\text{Rb}}{{\text{O}} _{\text{2}}}\,\,\,$

  4. ${\text{R}}{{\text{O}} _{\text{2}}}\,\,\,$


Correct Option: C

Match the following,regarding nature of the oxides
Column-I                                               Column-II
a. ${ N } _{ 2 }O$                         $       (i)Basic$

b. $ BaO$                                       $  (ii)Amphoteric $
            
c. $ { As } _{ 2 }{ O } _{ 3 }$            $     (iii)Acidic$

d. $ { Cl } _{ 2 }{ O } _{ 7 }$           $      (iv) Neutral$

  1. a(ii),b(i),c(iii),d(iv)

  2. a(iv),b(i),c(iii),d(ii)

  3. a(iv),b(i),c(ii),d(iii)

  4. a(ii),b(i),c(iv),d(iii)


Correct Option: B

Amphoteric oxides are:

  1. $SnO, SnO _2$

  2. $GeO, GeO _2$

  3. both (a) and (b)

  4. None of these


Correct Option: A
Explanation:

 Amphoteric oxide is one that reacts with both acids and bases to form salt and water. Thus,  SnO and SnO2 react with both HCl (an acid) and NaOH (base) to give salt and water.


GeO and GeO2 are not well characterized. It is amphoteric dissolving in acids to form germanium(II) salts and in alkali to form trihydroxy germanates or germinates and the GeO has not reacted both the acid and base so GeO is not an Amphoteric.

So the correct answer is A

Which of the following compounds is amphoteric?

  1. $Cr{(OH)} _{2}$

  2. $Fe{(OH)} _{2}$

  3. $Cr{(OH)} _{3}$

  4. $Fe{(OH)} _{3}$


Correct Option: C
Explanation:

$ Cr(OH) _3$ reacts with bases (hydroxide ions) to give $ [Cr(OH) _6]^{3-}$. It also reacts with acids (hydrogen ions) to give $ [Cr(H _2O) _6]^{3+}$ 


Hence,it act as amphoteric dissolve in both acid and base.

Thus,option C is correct.

Which of the following set contains oxide in the sequence, basic, amphoteric and acidic respectively?

  1. $SO _2,\, P _2O _5,\, CO$

  2. $BaO,\, Al _2O _3,\, SiO _2$

  3. $CaO,\, SiO _2,\, Al _2O _3$

  4. $Al _2O _3.\, CO _2,\, CO$


Correct Option: B
Explanation:
Generally Group 1 and Group 2 elements form bases called base anhydrides or basic oxides. Basic oxides are the oxides of metals. If soluble in water, they react with water to produce hydroxides. These metallic oxides are known as basic anhydrides. They react with acids to produce salts
E.g.-$BaO$
Acidic oxides are the oxides of non-metals (Groups 14-17) and these acid anhydrides form acids with water.
$SiO _2$
An amphoteric solution is a substance that can chemically react as either acid or base. For example, when $HSO _4^-$ reacts with water it will make both hydroxide and hydronium ions:
$Al _2O _3$

Which of the following set contains only amphoteric oxides?

  1. $ZnO,\, PbO,\, SnO,\,Al _2O _3$

  2. $ZnO,\, BaO,\, SO _2, CO$

  3. $CO,\, PbO,\, BaO _2,\, SO _2$

  4. $P _2O _5,\, N _2O _5,\, CI _2O _7,\, BaO$


Correct Option: A
Explanation:

An amphoteric solution is a substance that can chemically react with either acid or base. For example, when $HSO _4^-$ reacts with water it will make both hydroxide and hydronium ions. Amphoteric oxides are metallic oxides, which show both basic as well as acidic properties. When they react with an acid, they produce salt and water, showing basic properties. While reacting with alkalies they form salt and water showing acidic properties.  A common example of an amphoteric oxide is aluminium oxide, Zinc Oxide, SnO, PbO.

Which of the following is amphoteric in nature?

  1. $HClO _4$

  2. $NaOH$

  3. $Zn(OH) _2$

  4. None of these


Correct Option: C
Explanation:

$Zn(OH) _2$   amphoteric in nature
$HClO _4$      strong acid
$NaOH$         strong base

A basic oxide will be formed by the element:

  1. $K$

  2. $S$

  3. $P$

  4. $Kr$


Correct Option: A
Explanation:

Basic oxides will be formed by metals. Potassium is a metal and it forms basic oxides.

Which of the following oxides react with both $HCl$ and $NaOH$?

  1. $CaO$

  2. ${N} _{2}{O} _{5}$

  3. ${CO} _{2}$

  4. $ZnO$


Correct Option: D

The metals which can produce amphoteric oxides are:

  1. sodium and aluminium

  2. zinc and potassium

  3. calcium and sodium

  4. aluminium and zinc


Correct Option: D
Explanation:

'$Al$' and '$Zn$' reacts with both acids and bases. So, these are amphoteric in nature. So, oxides of these elements are amphoteric oxides. 

Out of the following oxides, the amphoteric oxide is:

  1. $Fe _2O _3$

  2. $Al _2O _3$

  3. $P _2O _5$

  4. $N _2O$


Correct Option: B
Explanation:

Aluminium reacts with acids and bases. So, it is amphoteric in nature. The oxide of an amphoteric element is called amphoteric oxide. So, $Al _{2}O _{3} $ is an amphoteric oxide.

One of the following is not a neutral oxide. This is:

  1. $CO$

  2. $H _2O$

  3. $N _2O$

  4. $Na _2O$


Correct Option: D
Explanation:

Sodium is a metal and metal oxides are basic in nature. So, $Na _{2} O$ is a basic oxide. It is not neutral oxide.

Which oxide is neutral state?

  1. $CO _2$

  2. $SO _2$

  3. $P _2O _5$

  4. $N _2O$


Correct Option: D
Explanation:

${ N } _{ 2 }O,CO,{ H } _{ 2 }O$ these are some samples of neutral oxides.

Pick the group which does not contain a neutral oxide.

  1. $NO _2, P _4O _{10}, Al _2O _3, NO$

  2. $MgO, N _2O _5, SO _3, N _2O$

  3. $CO _2, SO _3, CaO, XeO _3$

  4. $CO, SiO _2, SnO _2, Na _2O _3$


Correct Option: A
Explanation:

Neutral oxide are those which do not react with acids as well as bases such as $NO,{ N } _{ 2 }O,CO,{ O } _{ 2 }{ F } _{ 2 }$.

So only option $C$ does not contain neutral oxide.

In view of the signs of $\Delta _{r}G^{0}$ for the following reactions :
$PbO _{2} +Pb \rightarrow 2PbO, \Delta _ {r}..G..^{0},0$
$SnO _{2} +Sn \rightarrow 2SnO, \Delta _ {r}..G..^{0},0$

  1. For lead +2, for tin +2

  2. For lead +4, for tin +4

  3. For lead +2, for tin +4

  4. For lead +4, for tin +2


Correct Option: A

Among the following which one has more acidic character?

  1. $B _{2}O _{3}$

  2. $CO _{2}$

  3. $N _{2}O _{3}$

  4. None of these


Correct Option: A
Explanation:

$B _2O _3$ is more acidic than $CO _2$ and $N _2O _5$ because oxides of elements of 13th group of modern periodic table is more acidic than than 14th and 15th group elements.

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