0

Properties of natural resources - class-IX

Description: properties of natural resources
Number of Questions: 60
Created by:
Tags: properties of natural resources chemistry hydrogen and its compounds hydrogen water environmental science
Attempted 0/59 Correct 0 Score 0

The density of pure water is:

  1. 0.1 g/cm$^{3}$

  2. 1 g/cm$^{3}$

  3. 100 g/cm$^{3}$

  4. 1 kg/cm$^{3}$


Correct Option: B
Explanation:

Density is the ratio of mass per unit volume.
The density of pure water is $1 g / cm^{3}$ or $1000 kg / m^{3}$.

Specific heat of water is:

  1. very low

  2. medium

  3. sometimes high and sometimes low

  4. none of the above


Correct Option: D
Explanation:

The specific heat of water is $1$ $calorie/gm^oC=4.186$ $Joule/gm^oC$, which is higher than another common substance.

So, none of the above statement is true for specific heat of water.

The density of water is:

  1. $1\ g/cm$$^3$

  2. $20\ g/cm$$^3$

  3. $2\ g/cm$$^3$

  4. $0.1\ g/cm$$^3$


Correct Option: A
Explanation:

The density of water is $1 g/cm^{3}$. Density is a ratio of Mass to the Volume. 1 meter long, 1 meter wide, 1 meter high storage tank can store 1,000 kg mass of water. So the density of water is 1. Therefore 1 kg water= 1 litre water(approximately).

Pure water has a pleasant taste.

  1. True

  2. False


Correct Option: B
Explanation:

Pure water is tasteless. As it does not have any impurities(minerals, salts). So, the above statement pure water has a pleasant taste is false.

Water has the maximum density at $ 0^{\circ}C$.

  1. True

  2. False


Correct Option: B
Explanation:

Pure water has maximum density at $4^oC$ when water is heated from $0^oC$ its volume decrease because its density increases and we can see this effect up to $4^oC$.

The boiling point of water is inversely proportional to the atmospheric pressure.

  1. True

  2. False


Correct Option: B
Explanation:

The boiling point of water is not proportional to the atmospheric pressure. As the elevation increases, atmosphere decreases because air is less dense at high altitudes. Because the atmospheric pressure is lower, the vapour pressure of the liquid needs to be lower to reach boiling point. Therefore, less heat is required to make the vapour pressure equal to the atmospheric pressure.

The density of water at  $0^{\circ} C $ is less than the density of water at $ 4^{\circ}C $.

  1. True

  2. False


Correct Option: A
Explanation:

The density of water at $0^oC$ is less than the density of water at $4^oC$. When water is heated from $0^oC$ its volume decreases because its density increase we can see this effect up to $4^oC$, afterward density decreases.

Ice floats over water as its density is less than that of water.

  1. True

  2. False


Correct Option: A
Explanation:

Ice floats over water as its density is about $9\%$ less dense than liquid. The orientation of hydrogen bonds causes molecules to push further apart which lowers its density (cage like structure).

The water pipes burst in cold countries in winter due to anomalous expansion of water.

  1. True

  2. False


Correct Option: A
Explanation:

The water pipes burst in cold countries in winter due to anomalous expansion of water. In cold countries, when temperature falls below $0^{\circ}$C, aquatic life can survive due to anomalous expansion of water. When the temperature of surrounding reaches upto $4^{\circ}$C, the upper surface of the pond will have maximum density and so it sinks to the bottom of the pond.

Distilled water is a good conductor of electricity.

  1. True

  2. False


Correct Option: B
Explanation:

Pure water or distilled water does not conduct electricity. In distilled water there are no impurities, there are no ions, there are only neutral (no charge) water molecules and these neutral molecules do not have charge, So, distilled water does not conduct electricity.

Weight of $1$ $mole$ of hydrogen $=1$ $g$
Weight of $1$ $mole$ of Oxygen $=16$ $g$
Water $=H _2+\cfrac{1}{2}O _2\longrightarrow H _2O$
So, the ratio of mass of Hydrogen to oxygen $=\cfrac{2}{16}=1:8$

Which property of water make it easy to contaminate and difficult to purify?

  1. Water is a universal solvent

  2. Tendency to dissolve a large number of substances

  3. Both A and B

  4. None of the above


Correct Option: C
Explanation:

The property of water make it easy to contaminate and difficult to purify is its tendency to dissolve a large number of substances. The ocean/sea water is not fit for drinking and washing because it contains high concentration of the dissolved salts.

Why water is called an universal solvent?

  1. Because plants use water for taking minerals from the soil

  2. Water can dissolve a wide variety of substances

  3. Water is clear and transparent

  4. None of the above


Correct Option: B
Explanation:

Water can dissolve a wide variety of substances the is why water is known as universal solvent. Plant use this property of water for taking minerals from the soil.

Pure water has the maximum density at $ 4^{\circ} C.$

  1. True

  2. False


Correct Option: A
Explanation:

Pure water has maximum density at $4^oC$. When we heat water from $0^oC$, its density increases up to $4^oC$ then density decreases. (Anomalous expansion of water)

Which one of the following is not a physical property of water?

  1. Water has low specific heat capacity

  2. It expands on cooling

  3. It is odorless and tasteless

  4. The boiling point of water is $100^\circ C$


Correct Option: A
Explanation:

Water has high specific heat capacity. The other options are physical properties of water.

Which of the following types of water is not in its free state?

  1. River water

  2. Well water

  3. Distilled water

  4. Rain water


Correct Option: C
Explanation:

Distilled water is purified water free of all dissolved salts. River, well and rain water is water in free state as collected in nature.

What is the molecular weight of water?

  1. 21

  2. 18

  3. 20

  4. 16


Correct Option: B
Explanation:

The atomic masses of O and H are 16 g/mol and 1 g/mol respectively.
The molecular formula of water is $H _2O$ and its molecular weight $2(1) + 16=18$ g/mol.
Note:
Water is one of the most precious resources on earth and is necessary for all living beings. We use water for different purposes like drinking, cooking, bathing, washing and many more activities. Pure water is colorless, odorless and tasteless.

When water is cooled it contracts until it reaches ________ and then it starts expanding.

  1. $37$

  2. $40$

  3. $0$

  4. $4$


Correct Option: D
Explanation:

At $4^oC$ the density of water is maximum and volume of water is minimum.

Which one of the following property is high in the case of water?

  1. Surface tension

  2. Specific heat

  3. Heat of vaporization and heat of fusion

  4. All of the above


Correct Option: D
Explanation:
Physical properties of water
1.Boiling Point and Freezing Point.
2.Surface Tension, Heat of 3.Vaporization, and Vapor Pressure.
4.Viscosity and Cohesion.
5.Solid State.
6.Liquid State.
7.Gas State.
8.High specific heat capacity.

At 4$^{\circ}$C, water starts expanding and continues to do so till 0$^{\circ}$C.

Is the above statement correct?

  1. True

  2. False


Correct Option: A
Explanation:

When water is heated from $0^oC$ its value decreases because its density increases and we can see this effect up to $4^oC$ because the density of ice is maximum at $4^oC$. Afterward the density decreases, the volume increases.

As, when we cool it from $4^oC$ its volume increases up to $0^oC$. At $0^oC$ latent heat of fusion converts it to a form of ice. So, the given statement is true.

The physical state of water is liquid at which of the following temperatures?

  1. $25^o C$

  2. $0^oC$

  3. $100^oc$

  4. none of these


Correct Option: A
Explanation:

At 0$ ^{\circ}C $, water exists as ice. 

At 100$ ^{\circ}C $, it exists as steam.
At 25$ ^{\circ}C $, water exists in liquid form.

At what temperature ,water have maximum density?

  1. $0^oC$

  2. $4^oC$

  3. $30^oC$

  4. $25^oC$


Correct Option: B

Water acts as a powerful ionizing solvent due to its dielectric constant.

  1. True

  2. False


Correct Option: A
Explanation:

Water acts as a powerful ionizing agent due to its high dielectric constant. Water has high polarity and forms hydrogen bonds.

Water is cooled from $4^{\circ}C$ to $0^{\circ}C$. It will:

  1. contract

  2. expand

  3. first contract, then expand

  4. first expand, then contract


Correct Option: B
Explanation:

Water is cooled from $4^{\circ}C$ to $0^{\circ}C$. It is called "Anomalous expansion of water", i.e. The expansion between 4 and 0 is due to the formation of larger clusters in the water molecules.
When water molecules go from $4^{\circ}C$ to $0^{\circ}C$, they are forming groups in small lattices, what increases volume and decreases density. When water ices, then all their molecules are forming that lattice, as mineral crystals do, with the volume expanded.
Above 
$4^{\circ}C$, thermal expansion sets as thermal vibrations of the OH bonds of water becomes more vigorous, tending to shove the molecules farther apart and water expands.
As a result of this water at 
$4^{\circ}C$ is denser than that at $0^{\circ}C$. This causes floating of ice on water during winter. Bursting of pipes is also due to anomalous expansion.
Thus, Option B is correct.

Water can be boiled in a paper cup.

  1. True

  2. False


Correct Option: A
Explanation:

Water boils at 100$^o$ while paper burns at 200$^o$. Thus water can be boiled in paper.

Water is a mixture.

  1. True

  2. False


Correct Option: B
Explanation:

Water is not a mixture but a compound. It has elements hydrogen and oxygen which are combined chemically with two hydrogen and one oxygen atoms. These cannot be separated by any physical means.

Pure water is a ________ conductor of electricity.

  1. good

  2. bad

  3. semi

  4. very good


Correct Option: B
Explanation:

Pure water is a bad conductor of electricity. This is because free electrons are not present in pure water which allow the flow of electricity. Pure water is a bad conductor of electricity.

Water in its pure form is a:

  1. good conductor of heat

  2. bad conductor of electricity

  3. good conductor of electricity

  4. none of these


Correct Option: B
Explanation:

Water in pure form is a bad conductor of electricity because of the absence of free electrons (salts and minerals) that allow the flow of electricity.

Which of the following is soluble in water ?

  1. salt

  2. sugar

  3. oxygen

  4. all of these


Correct Option: D
Explanation:

Salt and sugar are soluble in water and form solution with water. Oxygen is also water soluble because the aquatic animals are able to breathe because oxygen is present in the dissolved form. As temperature increases solubility decreases, that's why in Eutrophication there is high BOD.(Biological Oxygen Demand)

When we heat water, we can find bubbles coming from it. This shows that:

  1. water contains air

  2. air contains water

  3. hot water becomes bubbles

  4. None of these


Correct Option: A
Explanation:

When we heat water, we can find bubbles coming from it. This is because the solubility of gases decreases as the temperature increases and that is why the dissolved air bubbles go out from the water. Then as the boiling point of the water is reached ($100^{\circ}C$), water vapour starts to form inside the liquid in the form of bubbles.  

Hence, option (A) is correct.

Pure water is a ________ conductor of electricity.

  1. good

  2. bad

  3. either could be possible

  4. none of the above


Correct Option: B
Explanation:

Pure water is bad conductor of electricity due to lack of impurities (salts and minerals).

Pure water is:

  1. colourless and opaque

  2. colourless and transparent

  3. coloured and transparent

  4. colourless, odourless and transparent


Correct Option: D
Explanation:

Pure water, also known as purified water, is water from a source that has removed all impurities. Distilled water is the most common form of pure water. The water can be purified by carbon filtration, microporous filtration and ultraviolet oxidation. Some places use a combination of purification processes. Pure water is colorless, odorless and transparent.

The water pipes burst in winter because pipes contract at low temperature.

  1. True

  2. False


Correct Option: B
Explanation:

Water pipes burst because the water inside them expands as it gets close to freezing point and this causes an increase in pressure inside the pipe. When pressure gets too high for the pipe to contain it ruptures.

Water exists in which of the following state?

  1. solid

  2. liquid

  3. gas

  4. all of above


Correct Option: D
Explanation:

Water exists in solid state (ice), liquid state (water) and gaseous state (steam or water vapours).
Water is the only substance that exists on earth in all the three physical states: solid, liquid and gas. Earth has rivers, lakes and oceans in liquid form. 

Polar regions are covered with solid water called ice. Water absorb solar energy and evaporate and escape as water vapour.

Which of the following is a universal solvent?

  1. water

  2. alcohol

  3. acetic acid

  4. both A and B


Correct Option: A
Explanation:

Water is  a universal solvent.  Water is capable of dissolving a variety of different substances. It dissolves more substances than any other liquid. Water is important to every living thing on earth. Wherever water goes, either through the ground or through our bodies, it takes along valuable chemicals, minerals, and nutrients.

Water is ______ in nature?

  1. acidic

  2. basic

  3. neutral

  4. none of above


Correct Option: C
Explanation:

Water is neutral in nature.
Since pH is defined as the negative log of the hydrogen ion concentration, the pH of pure water is 7 or neutral. Pure water is neutral because the number of positive hydrogen ions produced is equal to the number of negative hydroxide ions.

Ice at $0 \ ^0C$ has a lower density than water $4^{\circ}C$ and hence floats on water.

  1. True

  2. False


Correct Option: A
Explanation:

$H _{2} O$ at 4$ ^{\circ}C $ has maximum density. Ondecreasing the temperature from 4$ ^{\circ}C $ to 0$ ^{\circ}C $, its density decreases. Ice has 0$ ^{\circ}C $ has also less density compared to water at 4$ ^{\circ}C $. So, ice floats on water. 

Pure water is a poor conductor of heat and electricity.

  1. True

  2. False


Correct Option: A
Explanation:

True bbecause, it doesn't contain any ions, salts or impurities, which are necessary for conduction of electricity.

Ratio of hydrogen to oxygen in water is:

  1. $2:1$

  2. $1:2$

  3. $7:1$

  4. $8:1$


Correct Option: A
Explanation:

The ratio of hydrogen to oxygen in water is 2:1.
Two molecules of the diatomic hydrogen gas, combine with one molecule of the diatomic oxygen gas to produce two molecules of water. In other words the ratio of hydrogen to oxygen is 2:1, the ratio of hydrogen to water is 1:1, and the ratio of oxygen to water is 1:2.
$2H _2 + O _2 \rightarrow 2H _2O$

When water gets converted into ice, its volume:

  1. incresaes

  2. decreases

  3. no change

  4. cannot say


Correct Option: A
Explanation:

When water gets converted into ice, its volume increases. 

By this process, water can be purified in a simple way:

  1. Freezing

  2. Melting

  3. Boiling

  4. Evaporating


Correct Option: C
Explanation:

By boiling, water can be purified in a simple way as the nonvolatile impurities remain back and pure water is condensed separately.

Which of the following is NOT soluble in water?

  1. Salt

  2. Sugar

  3. Oxygen

  4. Sand


Correct Option: D
Explanation:

Sand $(SiO _2)$ is not soluble in water.

Which property of water is used while washing clothes?

  1. Odour

  2. Colour

  3. Solubility

  4. Sand


Correct Option: C
Explanation:

Water is a good solvent. It combine with dirt and other particles with it when treated with soap, which is water soluble and form lather in water. Hence due to its solubility it is used while washing clothes. 

Statement 1: Water boils below ${100}^{o}C$ at high altitudes. 
Statement 2: Atmospheric pressure varies inversely with altitude.

  1. Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1

  2. Both the Statement 1 and Statement 2 are correct and Statement 2 is NOT the correct explanation of Statement 1.

  3. Statement 1 is correct but Statement 2 is not correct.

  4. Statement 1 is not correct but Statement 2 is correct.

  5. Both the Statement 1 and Statement 2 are not correct.


Correct Option: A
Explanation:

Pressure changes inversely with altitudes and boiling point directly proportional to pressure. Pressure and boiling points are low at high altitudes. So water boils below 100$ ^{\circ}C $.

Temporary hardness is caused due to the presence of:

  1. magnesium sulphate

  2. magnesium chloride

  3. calcium sulphate

  4. magnesium carbonate


Correct Option: D
Explanation:

Temporary hardness is caused due to the presence of carbonates of calcium and magnesium which can be removed by boiling the water.

Permanent hardness is caused due to:

  1. magnesium bicarbonate

  2. magnesium carbonate

  3. magnesium sulphate

  4. all of the above


Correct Option: C
Explanation:

Temporary hardness causes due to the presence of carbonates and bicarbonate ans permanent hardness is caused due to the presence of chlorides and sulphates.

Water has maximum density at

  1. Room temperature

  2. ${4}^{o}C$

  3. ${0}^{o}C$

  4. $-{4}^{o}C$


Correct Option: B
Explanation:
When Water is in its Solid Form (Ice) below $0^0 C$, it is forced into a regular Cage like Structure with small voids due to which the Volume of Ice is larger.
At $4^0 C$, the Cage like Structure of Ice starts to break and the molecules can slide along each other, closing the empy voids due to which momentarily the Volume of Water decreases. Due to decrease in Volume, Density increases because Density is inversely proportional to Volume.
As temperature rises to over $4^0 C$, the extra space needed by increased motion of water molecules starts being larger than the space gained due to structural changes and the molecules start to move away from each other due to which the Volume again increases and Density decreases.

Thus, Density maximum is reached at $4^0C$.

Molecular mass of water ______.

  1. $18 u$

  2. $16 u$

  3. $15 u$

  4. $10 u$


Correct Option: A
Explanation:

As we know the molecular formula of water is H2O which means that one molecule of water contain 2 atoms of hydrogen and 1 atom of oxygen.

Then weight of 1 atom of hydrogen= 1 u

so weight of 2 atom= 2 u

Weight of 1 atom of oxygen= 16 u

Then molecular weight of water= 2* weight of 1 atom of hydrogen+ weight of 1 atom of oxygen

Thus molecular weight of water is approximately 2+16 u = 18 u

During hydrate formation from aqueous solution water can be associated in different forms. Indicate the wrong combination. 
Coordinated water -$[Cr(H _{2}O) _{6}]^{3+}3Cl^{-}$
Interstitial water - $BaCl _{2}.2H _{2}O$
Hydrogen bonded water --$[Cu(H _{2}O) _{4}]^{2+}SO _{4}^{2-}.H _{2}O$

  1. (i)

  2. (ii)

  3. (iii)

  4. none of these


Correct Option: D
Explanation:
Coordinated water is water that is a ligand in a metal complex. The metal atom and the water molecules are held together by coordinate bonds.
Interstitial water is water that is present in the interstitial sites of a crystal lattice.
Hydrogen-bonded water is the water that that is linked to some other ion by hydrogen bonding.

A teacher one day pointed out to his students the peculiar fact that water is a unique liquid that freezes exactly at $0^oC$ and boils exactly at $100^oC$. He asked the students to find the correct statement based on this fact.


Which of the statements is true regarding the above fact?

  1. Water dissolves anything however sparingly the dissolution may be.

  2. Water is a polar molecule.

  3. Boiling and freezing temperatures of water were used to define a temperature scale.

  4. Liquid water is denser than ice.


Correct Option: C
Explanation:

Option (C) is correct.
Boiling and freezing temperatures of water were used to define a temperature scale.The scaling of zero degree centigrade is based on this fact.

________is known as the universal solvent.

  1. Alcohol

  2. Benzene

  3. Ether

  4. Water


Correct Option: D
Explanation:

Water is known as the universal solvent because it is capable of dissolving a variety different substances, which is why it is such a good solvent.

The density of water is not same at all temperatures because of its anomalous expansion. The density is maximum at:

  1. $0^{\circ}C$

  2. $4^{\circ}C$

  3. $40^{\circ}C$

  4. $100^{\circ}C$


Correct Option: B
Explanation:

Density of water is maximum at $4^{\circ}C$. 

On cooling from  $4^{\circ}C$ to $0^{\circ}C$ it expands and on heating from $0^{\circ}C$ to $4^{\circ}C$ it contracts. 
On heating above $4^{\circ}C$ it expands.

The freezing point of water is:

  1. $4^\circ C$

  2. $3 ^\circ C$

  3. $1 ^\circ C$

  4. $0^\circ C$


Correct Option: D
Explanation:

The temperature at which a liquid turns into a solid when cooled is called freezing point.
The freezing point of water is $0^\circ C$.

Water exists in ........... state(s).

  1. one

  2. two

  3. three

  4. four


Correct Option: C
Explanation:

Water exists in three states namely solid, liquid and gas in the form of ice, water and vapour.

Evaporation of water is:

  1. a process is which neither heat is evolved nor absorbed

  2. a process accompanied by chemical reaction

  3. an exothermic change

  4. an endothermic change


Correct Option: D
Explanation:

Evaporation is an endothermic process because water molecules must absorb heat from the surroundings to increase their kinetic energy. For example, sweat which cools the human body as it evaporates from the skin.

Hence (D) option is correct.

Ice is lighter than water as

  1. Lattice aggregates occupy more space.

  2. Cold water is extremely dense.

  3. Hydrogen bonds are absent in ice.

  4. Lattice aggregates are absent in ice.


Correct Option: A
Explanation:
When water freezes, water molecules form a crystalline structure maintained by hydrogen bonding. Solid water, or ice, is less dense than liquid water. Ice is less dense than water because the orientation of hydrogen bonds causes molecules to push farther apart, which lowers the density.

Ice has density less that $1\ g \ cm^{-3}$.

  1. True

  2. False


Correct Option: A
Explanation:

The density of ice is less than the density of water i.e., $1$ $g/cm^3$ due to its cage like structure of hydrogen bonds. The orientation of hydrogen bonds cause the molecules to push further apart which lowers its density. 

Statement 1: Ice is less dense than liquid water.
Statement 2: Water molecules are nonpolar.

  1. Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1.

  2. Both Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation of Statement 1.

  3. Statement 1 is correct but Statement 2 is not correct.

  4. Statement 1 is not correct but Statement 2 is correct.

  5. Both the Statement 1 and Statement 2 are not correct.



Correct Option: C
Explanation:

Statement 1: Ice is less dense than liquid water.
Hence, an ice cube floats in a glass of water.
Statement 2: Water molecules are polar due to electronegativity difference between O and H atoms and non linear structure of water molecule.
Hence, statement 1 is correct but statement 2 is not correct.

$I$. Melting is an exothermic process.
$II$. Heat energy will cause covalent bonds in water to break as water converts from the solid state to the liquid state.

  1. Statement $I$ is true, Statement $II$ is true

  2. Statement $I$ is true, Statement $II$ is false

  3. Statement $I$ is false, Statement $II$ is true

  4. Statement $I$ is false, Statement $II$ is false


Correct Option: D
Explanation:

Melting is endothermic. Melting process needs energy to convert it from solid to liquid state.

Ice melts when heat energy causes the molecules to move faster, breaking of hydrogen bonds between molecules to form liquid water. In the melting process, the water molecules actually absorb energy.

Which one of the following statements about water is false?

  1. Ice formed by heavy water sinks in normal water

  2. Water is oxidized to oxygen during photosynthesis

  3. Water can act both as an acid and as a base

  4. There is extensive intramolecular hydrogen bonding in the condensed phase


Correct Option: D
Explanation:

Water possesses intermolecular hydrogen bonding in the condensed phase rather than intramolecular hydrogen bonding. Therefore statement (D) is incorrect

- Hide questions