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Some important carbon compounds - class-X

Description: some important carbon compounds
Number of Questions: 19
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Tags: organic chemistry carbon and its compounds chemistry carbon compounds
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Give the balance equation for the following laboratory preparation :

Ethane from sodium propionate

  1. $CH _3CH _2COONa + NaOH \rightarrow C _2H _6 + Na _2CO _3$

  2. $CH _3CH _2COONa + 2NaOH \rightarrow C _2H _4 + Na _2CO _3$

  3. $CH _3CH _2COONa + NaOH \rightarrow C _2H _4 + Na _2CO _3$

  4. $CH _3CH _2COONa + 2NaOH \rightarrow 2CH _4 + Na _2CO _3$


Correct Option: A
Explanation:

Reaction:
$CH _3CH _2COONa + NaOH \rightarrow C _2H _6 + Na _2CO _3$

According to this reaction, ethanol is :
2C$ _2$H$ _5$OH + 2Na -----> 2C$ _2$H$ _5$ONa + H$ _2$

  1. Acidic in nature

  2. Basic in anture

  3. Amphoteric

  4. Neutral


Correct Option: A
Explanation:

As ethanol has donated $H^{+}$ it suggests that it has acidic nature. Acid is defined as the substance which has replaceable $H^{+}$ions. In the products side, it has donated and became the reason for the formation of hydrogen molecule. Hence, option A is the correct answer. 

 When ethanol react with sodium,which gas will produce?

  1. hydrogen

  2. oxygen

  3. sodium ethoxide

  4. carbon dioxide


Correct Option: A
Explanation:

If a small piece of sodium is dropped into some ethanol, it reacts steadily to give off bubbles of hydrogen gas and leaves a colourless solution of sodium ethoxide, $CH _3CH _2ONa$ and hydrogen gas is evolved.

$2C _2H _5OH + 2Na \rightarrow 2C _2H _5ONa + H _2$ Option A is correct.

Vinegar is a :

  1. 5-8% solution of acetic acid in water

  2. 25-30% solution of acetic acid in water

  3. 40-45% solution of acetic acid in water

  4. 45-50% solution of acetic acid in water


Correct Option: A
Explanation:

Vinegar is a liquid containing acetic acid and water. This acetic acid is produced by the fermentation of ethanol by acetic acid bacteria. It is mainly used as a cooking ingredient. It is a 5-8% solution of acetic acid in water and most easily available mild acid.

$ N{ a } _{ 2 }C{ O } _{ 3 }+2C{ H } _{ 3 }COOH\longrightarrow $ 

Which gas is produced in this reaction?

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

  2. $CO _2$

  3. $CO$

  4. $H _2$


Correct Option: B

$ NaOH+{ C }{ H } _{ 3 }COOH\longrightarrow C{ H } _{ 3 }COONa+{ H } _{ 2 }O $

This reaction is called : 

  1. oxidation reaction

  2. hydrogention reaction

  3. neutralisation reaction

  4. addition reaction


Correct Option: C
Explanation:

Acid and Base reacts to form Salt and Water. This reaction is called neutralisation reaction. In this, acid is acetic acid and base is sodium hydroxide. Salt ($CH _3COONa$) is formed.

Proof is defined as _______ the percentage by volume of alcohol in ethanol-water mixture.

  1. twice

  2. thrice

  3. half

  4. four times


Correct Option: A
Explanation:
The term was originally used in the United Kingdom and was equal to about  7/4 times the alcohol by volume (ABV). The UK now uses the ABV standard instead of alcohol proof. In the United States, alcoholic proof is defined as twice the percentage of ABV.

Which of the following will react with sodium metal?

  1. Ethanol

  2. Ethanal

  3. Ethene

  4. Ethane


Correct Option: A
Explanation:

$2CH _3CH _2OH + 2Na\longrightarrow 2CH _3CH _2ONa + H _2$
$2H _2O + 2Na\longrightarrow 2NaOH + H _2$

The organic acid present in vinegar is :

  1. methanoic acid

  2. ethanoic acid

  3. propanoic acid

  4. none of these


Correct Option: B
Explanation:

Vinegar is also known as acetic acid and water. Acetic acid is ethanoic acid produced by the fermentation of ethanol by acetic acid bacteria. Vinegar is a cooking ingredient and commercially produced by fast or slow fermentation processes. 

Acetic acid is:

  1. Methanoic acid

  2. Ethanoic acid

  3. Propanoic acid

  4. None of these


Correct Option: B
Explanation:

Acetic acid is Ethanoic acid $CH _3COOH$. It is also called vinegar.

Which of the following product is obtained during reaction of ethanoic acid with diazomethane in presence of $dil. HCl$?

  1. Methyl acetate

  2. Ethyl acetate

  3. Methyl formate

  4. Ethyl formate


Correct Option: A
Explanation:

Methyl acetate is obtained during reaction of ethanoic acid with diazomethane in presence of dil HCl.
$CH _3COOH + CH _2N _2 \xrightarrow {dil HCl} CH _3COOCH _3 + N _2$

Which of the following product(s) is$/$are obtained during the reaction of ethanoic acid with chlorine?

  1. Monochloroacetic acid

  2. Dichloroacetic acid

  3. Trichloroacetic acid

  4. All of the above


Correct Option: D
Explanation:

When ethanoic acid reacts with chlorine in the presence of acetic anhydride as catalyst it forms chloroacetic acid.

$CH _3COOH  + Cl _2 \rightarrow ClCH _2COOH + HCl$

Ethanol reacts with sodium and forms two products. These are:

  1. sodium ethanoate and hydrogen

  2. sodium ethanoate and oxygen

  3. sodium ethoxide and hydrogen

  4. sodium ethoxide and oxygen


Correct Option: C
Explanation:

The equation for the reaction between sodium and ethanol can be written as:
$2CH _{3}CH _{2}OH + 2Na \rightarrow 2CH _{3}CH _{2}ONa + H _{2}$
Therefore, the products formed are sodium ethoxide and hydrogen.

Write the type of reaction.
Ethanol is warmed with ethanoic acid to form ethyl acetate in the presence of concentrated $H _{2}SO _{4}.$

  1. Esterification reaction

  2. Neutralisation reaction

  3. Decomposition reaction

  4. Double displacement reaction


Correct Option: A
Explanation:

Reaction of ethanol with warm ethanoic acid to form ethyl acetate(an ester) and water can be written as:
$ C _{2}H _{5}OH +  CH _{3}COOH  \overset{H^{+}}{\rightarrow}   CH _{3}COOC _{2}H _{5}  +  H _{2}O$
(ethanol)      (ethanoic acid)             (ester)
Above reaction is an esterification reaction as an alcohol and an acid are combined to formed an ester. 

Which of the following represents saponification reaction?

  1. $CH _{3}COONa + NaOH \xrightarrow{CaO} CH _{4} + Na _{2}CO _{3}$

  2. $CH _{3}COOH + C _{2}H _{5}OH \xrightarrow{H _{2}SO _{4}} CH _{3} COOC _{2}H _{5} +H _{2}O$

  3. $2CH _{3}COOH + 2Na \rightarrow 2CH _{3} COONa + H _{2}$

  4. $CH _{3}COOC _{2}H _{5} + NaOH \rightarrow CH _{3} COONa + C _{2} H _{5}OH$


Correct Option: D
Explanation:

Saponification is the alkaline hydrolysis of esters to form soap and alcohol. Therefore, the correct answer is option D.

$CH _{3}COOC _{2}H _{5} + NaOH \rightarrow CH _{3}COONa + C _{2}H _{5}OH$
    Ester                         Alkali                Soap               Alcohol

Explain the given reactions with the examples.
Oxidation reaction :

  1. ${ C } _{ 2 }{ H } _{ 5 }OH\xrightarrow { Alk.KMn{ O } _{ 4 } } { C }{ H } _{ 2 }OH{ COOH }$

  2. ${ C } _{ 2 }{ H } _{ 5 }OH\xrightarrow { Alk.KMn{ O } _{ 4 } } { C }{ H } _{ 3 }{ CH _3 }$

  3. ${ C } _{ 2 }{ H } _{ 5 }OH\xrightarrow { Alk.KMn{ O } _{ 4 } } { C }{ H } _{ 3 }{ CH _2OH }$

  4. ${ C } _{ 2 }{ H } _{ 5 }OH\xrightarrow { Alk.KMn{ O } _{ 4 } } { C }{ H } _{ 3 }{ COOH }$


Correct Option: D
Explanation:

Ethanol is oxidised to ethanoic acid in the presence of alkaline
$KMnO _{4}$ on heating
$CH _{3}  CH _{2}  OH \xrightarrow[Heat]{Alk.  KMnO _{4}} CH _{3}COOH$

An organic compound 'A' produces a gas with brisk effervescence when sodium bicarbonate is added to it. The compound 'A' contains same number of carbons as in ethane. The compound 'A' reacts with ethanol to form a sweet smelling compound 'C' in presence of conc. $H _2SO _4$. A and C respectively are :

  1. ethanoic acid and ethyl ethanoate

  2. methanoic acid and ethyl methanoate

  3. ethanoic acid and sodium ethanoate

  4. methanoic acid and sodium methanoate


Correct Option: A
Explanation:

Ethanoic acid reacts with sodium bicarbonate, to form carbon dioxide which produces effervescence as: 


$CH _{3}COOH + NaHCO _{3} \rightarrow CH _{3}COONa + H _{2}O + CO _{2}$ 

Also, ethanoic acid reacts with ethanol to form the ester - ethyl ethanoate as follows: 


$CH _{3}COOH + C _{2}H _{5}OH \overset{conc.\ H _{2}SO _{4}}{\longrightarrow} CH _{3}COOCH _{2}CH _{3} + H _2O$ 

Thus, A is ethanoic acid and C is ethyl ethanoate.

Which of the following is a property of ethanol?

  1. Ionic compound

  2. Noble gas

  3. Polar covalent compound

  4. Nonpolar covalent compound

  5. Metallic substance


Correct Option: C
Explanation:

$C _2H _5OH$ has polar covalent $C-O$ bond due to significant electronegativity difference between $C$ and$ O.$ Similarly $O-H$ bond is also polar covalent due to significant electronegativity difference between $O$ and $H$ atoms.
A covalent bond is formed by sharing of electrons. When this electron sharing is to an equal extent, the bond is non polar covalent. Otherwise the bond is polar covalent.

Name the process for ethanol to ethene conversion and reactants used.
  1. hydrogenation of ethanol in the presence of concentrated $H _{2}SO _{4}.$

  2. dehydration of ethanol in the presence of concentrated $H _{2}SO _{4}.$

  3. oxidation of ethanol in the presence of concentrated $H _{2}SO _{4}.$

  4. reduction of ethanol in the presence of concentrated $H _{2}SO _{4}.$


Correct Option: B
Explanation:

Ethanol can be converted to ethene as:

    $CH _{3}CH _{2}OH \xrightarrow[hot]{conc.H _{2}SO _{4}} CH _{2}= CH _{2} + H _{2}O$

In above reaction, dehydration of ethanol takes place in the presence of concentrated sulphuric acid.
Hence, the correct option is B.

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