Water is a transparent, tasteless, and odorless chemical substance in its pure form, composed of two hydrogen atoms bonded to one oxygen atom (H2O). It is essential for all forms of life on Earth, making up about 71% of the planet’s surface. Water is a fundamental component of many biological processes and plays a crucial role in various functions, including hydration, temperature regulation, and transportation of nutrients within organisms.
Water MCQs with answers practice now
Water exists in three main states: solid (ice), liquid (water), and gas (water vapor). It can undergo phase changes between these states depending on the temperature and pressure conditions. Water also has a high specific heat capacity, allowing it to absorb and release heat energy without undergoing significant temperature changes, making it important for climate regulation.
Water has many unique properties, such as surface tension, capillary action, and high solvent capability, which make it an excellent medium for chemical reactions and biological processes. It is known as the universal solvent because it can dissolve a wide variety of substances, which enables it to transport and deliver essential nutrients to cells.
Water is vital for human survival, and it is recommended to drink an adequate amount of water each day to maintain proper hydration. It is also used for various purposes, including agriculture, industry, and sanitation. Access to clean and safe drinking water is a global concern, as many regions face challenges related to water scarcity and contamination.
Overall, water is a remarkable and indispensable resource that supports life and sustains ecosystems on our planet.
Water MCQs with answers
1. Which of the following is the chemical formula for water?
a) H2O
b) CO2
c) NaCl
d) C6H12O6
2. What is the primary role of water in the human body?
a) Providing energy
b) Regulating body temperature
c) Aiding in digestion
d) Building muscle mass
3. Water covers approximately what percentage of the Earth’s surface?
a) 20%
b) 50%
c) 70%
d) 90%
4. At what temperature does water boil at sea level?
a) 100°C (212°F)
b) 50°C (122°F)
c) 0°C (32°F)
d) -10°C (14°F)
5. Water is considered a universal solvent because it:
a) Dissolves all substances completely
b) Has a neutral pH
c) Conducts electricity
d) Dissolves a wide range of substances
6. Which of the following is an example of a waterborne disease?
a) Malaria
b) Tuberculosis
c) Cholera
d) Diabetes
7. Water freezes at what temperature?
a) 0°C (32°F)
b) 100°C (212°F)
c) -10°C (14°F)
d) 50°C (122°F)
8. The process of water changing from a liquid to a gas is called:
a) Evaporation
b) Condensation
c) Sublimation
d) Boiling
9. Which of the following is true about the density of water?
a) Water is denser than most liquids.
b) Water is less dense than most liquids.
c) Water has the same density as most liquids.
d) Density of water varies based on temperature.
10. What is the scientific term for the process of water moving through a plant and evaporating from its leaves?
a) Transpiration
b) Respiration
c) Photosynthesis
d) Absorption
11. Which of the following is an example of a renewable source of water?
a) Underground aquifers
b) Glaciers
c) Lakes and rivers
d) Desalination plants
12. Water is often called the “universal solvent” because:
a) It can dissolve any substance completely.
b) It can dissolve most substances partially.
c) It can dissolve only ionic compounds.
d) It cannot dissolve any substances.
13. What is the term for the process of water vapour turning directly into ice without first becoming a liquid?
a) Melting
b) Condensation
c) Sublimation
d) Freezing
14. The process of removing impurities from water to make it safe for consumption is called:
a) Filtration
b) Distillation
c) Purification
d) Oxidation
15. The average human can survive without water for approximately:
a) 1 day
b) 1 week
c) 1 month
d) 3 months
16. Water molecules are held together by:
a) Ionic bonds
b) Covalent bonds
c) Metallic bonds
d) Hydrogen bonds
17. What is the term for the amount of water vapour present in the air?
a) Humidity
b) Precipitation
c) Saturation
d) Condensation
18. Which of the following is true about the pH of pure water?
a) It is acidic.
b) It is basic.
c) It is neutral.
d) It varies depending on temperature.
19. What is the process by which plants absorb water through their roots?
a) Transpiration
b) Osmosis
c) Photosynthesis
d) Capillary action
20. Which of the following is the main source of freshwater on Earth?
a) Oceans
b) Glaciers and ice caps
c) Underground aquifers
d) Lakes and rivers
Water MCQs with answers class 8
1. Water has the highest density at:
a) 0°C (32°F)
b) 4°C (39.2°F)
c) 100°C (212°F)
d) -10°C (14°F)
2. The process of water vapour turning back into a liquid is a form of:
a) Physical change
b) Chemical change
c) Nuclear change
d) Biological change
3. Water has a unique property known as surface tension, which allows it to:
a) Absorb heat efficiently
b) Conduct electricity
c) Form droplets and maintain shape
d) Dissolve substances completely
4. Which of the following is a method of water conservation?
a) Taking longer showers
b) Leaving taps running while brushing teeth
c) Using a dishwasher instead of hand-washing dishes
d) Watering plants during the hottest part of the day
5. Water is essential for which of the following bodily functions?
a) Regulating blood pressure
b) Maintaining healthy kidneys
c) Lubricating joints
d) All of the above
6. Which of the following factors does NOT affect the boiling point of water?
a) Altitude
b) Pressure
c) Salinity
d) Temperature
7. Water scarcity refers to:
a) The lack of clean drinking water globally
b) The excess of water in a given area
c) The lack of water bodies on Earth
d) The high concentration of minerals in water
8. Which of the following is NOT a property of water?
a) High boiling point
b) Low surface tension
c) Universal solvent
d) High heat capacity
9. The process of water moving from an area of high concentration to an area of low concentration through a semipermeable membrane is known as:
a) Filtration
b) Osmosis
c) Diffusion
d) Absorption
10. The pH scale is used to measure the:
a) Temperature of water
b) Density of water
c) Acidity or alkalinity of water
d) Dissolved oxygen content of water
11. Which of the following is NOT a source of water pollution?
a) Industrial waste
b) Agricultural runoff
c) Renewable energy sources
d) Sewage discharge
12. The process of water vapour forming droplets on a cold surface is called:
a) Precipitation
b) Condensation
c) Evaporation
d) Sublimation
13. The process of converting seawater into freshwater by removing salt and other impurities is called:
a) Filtration
b) Distillation
c) Desalination
d) Purification
14. The maximum density of water occurs at:
a) 0°C (32°F)
b) 4°C (39.2°F)
c) 100°C (212°F)
d) -10°C (14°F)
15. The melting point of ice is equivalent to the:
a) Freezing point of water
b) Boiling point of water
c) Sublimation point of water
d) Evaporation point of water
16. Water has a unique property that causes it to have a higher boiling point compared to similar-sized molecules. This property is known as:
a) Surface tension
b) Cohesion
c) Adhesion
d) Hydrogen bonding
How much of the Earth’s surface is covered by water?
Approximately 71% of the Earth’s surface is covered by water, mostly in the form of oceans, seas, and other bodies of water.
What is the importance of water for the human body?
Water is crucial for the human body as it helps regulate body temperature, aids in digestion, transports nutrients, and flushes out waste products.
How much water should a person drink each day?
It is generally recommended to drink about eight 8-ounce glasses of water per day, which is roughly equivalent to 2 liters or half a gallon.
Can you survive without drinking water for several days?
The human body can only survive for a few days without water, depending on factors such as climate, physical activity, and overall health.
How does water reach our homes?
Water is typically supplied to homes through a network of pipes connected to a water treatment plant, which purifies and distributes water to households.
Why does water sometimes have a taste or odor?
Water can acquire taste or odor due to the presence of dissolved minerals, chemicals, or organic matter, which can vary depending on the water source.
What is the water cycle?
The water cycle is the continuous movement of water between the Earth’s surface, the atmosphere, and back again through processes like evaporation, condensation, and precipitation.
Can water exist in liquid form at temperatures below freezing?
Yes, water can exist in a liquid state below freezing point if it is under high pressure. This is why water can remain liquid inside some pressurized systems.
How does water contribute to erosion and shaping of the Earth’s surface?
Water plays a significant role in erosion by carrying and transporting sediments, wearing away rocks, and shaping landforms such as rivers, valleys, and canyons.
How does water pollution affect ecosystems and human health?
Water pollution, caused by the release of harmful substances into water bodies, can harm aquatic life, contaminate drinking water sources, and pose risks to human health through consumption or contact with polluted water.
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