G10 Chem-15

Chem-15.1 What is the main reason behind the significance of water for living organisms?

• a) Water provides an environment for animals and plants that live in water.
• b) Water is an essential and major component of each and every living cell.
• c) Water is a source of food for all living organisms.

Chem-15.2 What is the percentage of water present in the human body?

• a) 30%
• b) 50%
• c) 70%

Chem-15.3 Which of the following is not a daily life use of water mentioned in the text?

• a) Cooking
• b) Drinking
• c) Driving

Chem-15.4 What has been a major factor in determining human health and welfare since ages?

• a) Quality of air
• b) Quality of soil
• c) Quality of drinking water

Chem-15.5 What is the greatest threat to the supplies of water especially in urban areas?

• a) Groundwater depletion
• b) Water shortage
• c) Waterborne toxic chemicals

Chem-15.6 What is the percentage of potable water on the Earth?

• a) 0.1%
• b) 0.2%
• c) 0.3%

Chem-15.7 What is the freezing point of pure water?

• a) 0°C
• b) -10°C
• c) 100°C

Chem-15.8 What is the maximum density of water?

• a) 1 gcm-3 at 4°C
• b) 2 gcm-3 at 4°C
• c) 0.5 gcm-3 at 4°C

Chem-15.9 What is the exceptional heat capacity of water compared to that of rocks?

• a) About 2 times greater
• b) About 4 times greater
• c) About 6 times greater

Chem-15.10 What is responsible for keeping the Earth’s temperature within limits?

• a) Water’s boiling point
• b) Water’s freezing point
• c) Water’s high heat capacity