Water and Its Composition

Q. The consequences of the anomalous expansion of water are:

1. increasing mass of water.
2. bursting of water pipe’s during winter.
3. preservation of the aquatic life during the very cold weather.
4. icebergs floating on water.

Q.

A blade can float on water because of _____ of water.

1. heat capacity

2. boiling point

3. freezing point

4. surface tension

Q.

Name the gas involved when metals react with dilute acid

Q.

“Dissolution of quick lime in water is an exothermic reaction.” Explain.

Q. A compound of sodium chloride contains ___atom of sodium and ___atom of chlorine.

1. 1 and 1
2. 1 and 2
3. 1 and 3
4. 1 and 4

Q.

Why is water useful to life on the earth?
(i) It maintains ecological balance.
(ii) It sustains life.
(iii) It is necessary for respiration in aquatic organisms.

1. Only (i) and (ii)

2. (i) , (ii) and (iii)

3. Only (ii) and (iii)

4. Only (i) and (iii)

Q. Which among the following is the universal solvent?

1. Water
2. Nitrogen
3. Oxygen
4. Hydrogen

Q. Hydrophilic molecules are while hydrophobic molecules are .

1. acids
2. water repellants
3. water absorbents
4. bases

Q. Which of the following plays an important role in providing heat during water cycle?

1. Clouds
2. Moon
3. Sun
4. Wind

Q.

Q.

What is the specific heat capacity of water?

1. 4.18 kJ / g C

2. 4.18 Cal

3. 4.18 J/ g C

4. 4.18 J Kg / C

Q. Temporary hardness of water can be removed by __________ of water.

Q. A compound of sodium chloride contains ___atom of sodium and ___atom of chlorine.

1. 1 and 3
2. 1 and 4
3. 1 and 2
4. 1 and 1

Q. If density of water is 1, and an object sinks into it. What can be said about density of the object?

1. Equal to 1
2. Greater than 1
3. Lesser than 1
4. Lesser than 0

Q. If the mass of a copper vessel is 945 grams, then find its volume in $c{m}^3$, given, density of copper is $2.7g/c{m}^3$.

1. 350

Q. Due to surface tension, rain drops have tendency to acquire shape.

1. spherical
2. cylindrical
3. conic
4. cubic

Q.

We can broadly classify water into saline water, frozen water and usable surface water. Which of the following correctly represents their relative amount on the Earth?

1. Frozen water > Usable surface water > Saline water
2. Saline water > Frozen water > Usable surface water
3. Saline water > Usable surface water > Frozen water
4. Usable surface water > Frozen water > Saline water

Q. Fresh water can be found in:

1. Rivers
2. Sea
3. Lakes
4. Ocean
5. Ponds
6. Wells
7. Underground
8. Glaciers

Q. Water is an important natural resource because:

1. it maintains ecological balance.
2. it sustains life.
3. it is necessary for respiration in aquatic organisms.
4. it is essential for photosynthesis.

Q. Give Reason:
Dilute hydrochloric acid reacts with magnesium liberating hydrogen, but the same is not liberated when the acid reacts with lead.

Q. The continuous cycles of condensation and evaporation results in ______.

1. rain
2. dew
3. mist
4. wind

Q.

Choose the correct statement(s).

1. Pure water changes the colour of blue litmus to red.

2. Pure water changes the colour of red litmus to blue.

3. Water has dissolved oxygen.

4. Electrolysis of water produces hydrogen and oxygen.

Q.

The percentage of the Earth's surface covered by water is approximately:

1. 75%
2. 60%
3. 85%
4. 50%

Q.

Water is used in industries as

1. A solvent and a coolant

2. A raw material

3. Transporting agent

4. All of the above

Q.

The amount of usable water on earth is limited.

1. False
2. True

Q. During evaporation, the molecules present at the top and the bottom of a liquid escape at the same time.

1. False
2. True

Q. Only 3% of the Earth's water is freshwater.

1. True
2. False