Water

Q. Justify the statement ' plants and animals are p^{​​​​​​H}​​​​​ sensitive' by giving two examples.

Q.

Which domain of the earth consists of water in all its forms?

1. Lithosphere

2. Hydrosphere

3. Biosphere

4. Atmosphere

Q.

12. Which is not a part of the water cycle?

1. Cloud formation

2. Rain

3. Drinking by animals

4. Sun

Q. How to identify acids and bases experimentally?

Q. Is oil a solution or a compound?

Q. In which pH range our body works?

Q.

How does water get polluted?

1. Due to the dumping of sewage into rivers or lakes

2. Due to the dumping of wastes from factories into rivers or lakes

3. Due to oil spills in the oceans.

4. None of these

Q.

Water ____ in nature is a continuous process

Q. This section contains 1 Assertion-Reason type question, which has 4 choices (a), (b), (c) and (d) out of which ONLY ONE is correct.
इस खण्ड में 1 कथन-कारण प्रकार का प्रश्न है, जिसमें 4 विकल्प (a), (b), (c) तथा (d) दिये गये हैं, जिनमें से केवल एक सही है।

A : Acidic or basic solution in water conducts electricity.
A : जल में अम्लीय या क्षारीय विलयन विद्युत का चालन करता है।

R : Acidic and basic solutions in water produce hydrogen and hydroxide ions respectively.
R : जल में अम्लीय तथा क्षारीय विलयन क्रमशः हाइड्रोजन तथा हाइड्रॉक्साइड आयन देते हैं।

1. Both (A) and (R) are true and (R) is the correct explanation of (A)
   
   (A) तथा (R) दोनों सही हैं तथा (R), (A) का सही स्पष्टीकरण है
2. Both (A) and (R) are true but (R) is not the correct explanation of (A)
   
   (A) तथा (R) दोनों सही हैं लेकिन (R), (A) का सही स्पष्टीकरण नहीं है
3. (A) is true but (R) is false
   
   (A) सही है लेकिन (R) गलत है
4. (A) is false but (R) is true
   
   (A) गलत है लेकिन (R) सही है

Q.

Which of the following sources of water will lead to infiltration of the water table?

1. Flowing rivers

2. Rainfall

3. Lakes

4. All of these

Q. Covering 71 percent of Earth's surface, the oceans play an essential role in maintaining the conditions for human existence on land, moderating temperature by the absorption of heat and carbon dioxide, and giving pure water back to the atmosphere through evaporation.

1. Covering 71 percent of Earth's surface, the oceans play an essential role in maintaining the conditions for human existence on land, moderating
2. The oceans cover 71 percent of Earth's surface and play an essential role in maintaining conditions for human existence on land, and by moderating
3. Covering 71 percent of Earth's surface and playing an essential role in maintaining the conditions for human existence on land, the oceans moderate
4. The oceans cover 71 percent of Earth's surface, play an essential role in maintaining the conditions for human existence on land, and moderate
5. The oceans cover 71 percent of Earth's surface, playing an essential role in maintaining the conditions for human existence on land, and they moderate

Q.

You must have seen many advertisements about conservation of water. We know that $\frac{3}{4}$th of earth's surface is filled with water. That is a huge amount of water. Then why should we conserve water? [3 MARKS]

Q.

Name a source of fresh water. [1 MARK]

Q. The water of crystallisation is the fixed number of _________ molecules in one formula unit of salt.

1. hydrogen
2. water
3. oxygen
4. hydroxide

Q. ArrageA the following in an increasing oedorof there pH:NaOH solution, blood, lemon juice

Q.

What is the major source of fresh water in the city/town where you live?

1. Glaciers

2. Antarctica

3. Rivers and local water bodies

4. None of the above

Q. The pH values of certain familiar substances are given below

Substance	pH value
Blood	7.4
Baking soda	8.2
Vinegar	2.5
Household ammonia	12

Analyse the data in the table and answer the following questions
a) Which substances are acidic in nature?
b) Which substances are basic in nature?

Q. Give reasons to justify water is a compound not a mixture.

Q.

Name the phenomenon which explains the drop in the water level of a lake during the summer season.

Q. What are compounds

Q.

14. Describe water cycle?

Q.

Define water cycle. Rearrange the steps of a water cycle to get the correct sequence.

i. Water evaporates from the water reservoirs present on land.
ii. Water exists in the form of water vapours in the atmosphere.
iii. Condensation of the water droplets converts them into clouds.
iv. Rainwater again flows into different forms of water reservoirs on land.
v. When the clouds become big and heavy they fall down as rain.
vi. Water vapours, due to cooling, form droplets using dust particles as nuclei.