Importance of water - class-XI

Compounds can exist in all three states(solid, liquid, gas) provided that they can be heated/cooled enough(to their respective boiling/melting points). Thus water, ice, and steam all are compounds of hydrogen and oxygen.

The levelling effect refers to the inability of a solvent to distinguish between the strengths of strong acids or bases. Water is a leveling solvent for strong acids; however, the question asks where it is minimum. In non-leveling or differentiating solvents, the effect is minimized.

Water is made of Hydrogen and Oxygen, which are gases at STP. 

Dissolved salts in potable water provide taste and are useful for living being like calcium and magnesium ions.

$22^{nd}$ of March every year is celebrated as the world water day.

Burning hydrogen with oxygen give rise to formation of water.

Henry Cavendish showed that water is made up of hydrogen and oxygen.

The number of molecules of water is 5. The formula is $CuSO _4. 5H _2O$.

The colour of hydrated copper sulphate is blue.

Anhydrous cobalt(II) chloride is blue. When it reacts with water, it forms the hexahydrate complex CoCl2.6H2O, which is pink.

The colour of anhydrous copper sulphate is white.

Approximately 97 percent of Earth's water is saline, found in the oceans. Among the options provided, 93.7 percent is the closest accepted value in many textbooks.

H2S is a reducing agent and H2SO4 is an oxidizing agent. The reaction typically produces sulfur (S), sulfur dioxide (SO2), and water (H2O). H2O2 is not a product of this reaction.

The earth appears blue from outer space because 70% of the earth's surface contains water, i.e., water bodies like oceans, seas, rivers, lakes, etc.

The property of the surface of a liquid that allows it to resist an external force, due to the cohesive nature of its molecules is called surface tension. while washing clothes, detergents reduce the surface tension of the water molecule which causes the formation of foam and cleaning of clothes. 

Hard water contains chlorides, carbonates and bicarbonates of sodium and magnesium ions which combine with soap micelles and do not give lather with soap.

The number of molecules of water in $CoCl _2$ is 6. So the formula becomes $CoCl _2.6H _2O$.

Rain water and distilled water does not contain impurities.

The molecular weights of ammonia and water are 17 g/mole and 18 g/mole respectively.
4 moles of ammonia gives 6 moles of water.
$4 \times 17 = 68$ g of ammonia will give $6 \times 18 = 108$ g of water.
16.00 g of ammonia will give $16.00 \times \dfrac {108}{68} = 25.3$ g of water.

The molecular weights of ammonia, oxygen and water are 17 g/mole, 32 g/mole and 18 g/mole respectively.

66.00 g ammonia $= \dfrac {66.00}{17} = 3.88$ moles ammonia.
54.00 g oxygen $=\dfrac {54.00}{32.0}=1.6875$ moles oxygen.
4 moles ammonia reacts with 5 moles oxygen.
Hence, 3.88 moles ammonia will react with $3.88 \times \dfrac {5}{4} = 4.85$ moles oxygen but only 1.6875 moles oxygen are present. Hence oxygen is the limiting reagent.

5 moles of oxygen gives 6 moles of water.
1.728 moles of oxygen will give $1.6875 \times \dfrac {6}{5} = 2.025$ moles of water.
The mass of water obtained is $18 \times 2.025 = 36.51$ g of water.

Dissolved salts in water are important because
(A) They provide taste
(B) Growth of plants
(C) Minerals essential for body
Water contains dissolved salts which provide taste to water for drinking purposes. Also these salts are essential for growth and development of plants. These dissolved salts provide the essential minerals which are required for growth of body.

Dissolved gases can be removed from water by boiling.
Water contains certain gases in dissolved state. The higher the temperature of a solution becomes, the less a gas dissolves provided it doesn't react with the solvent. Consequently, heating/boiling a solution can expel the remaining gas.

Anhydrous $CoCl _2$ is blue in colour.

The gas-phase oxidation of hydrogen has been extensively studied over a wide range of temperatures and pressures.

Lotic ecosystems refer to flowing water bodies such as rivers, streams, and springs, as opposed to lentic systems which are standing water bodies.

Human faeces contains various pathogens and bacteria, which often contaminate water sources, leading to waterborne diseases.

According to Henry's Law, the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid.

Lotic water refers to moving water. Streams, rivers, and springs are all examples of flowing water systems.

In a water molecule (H2O), the oxygen atom is sp3 hybridized, resulting in a tetrahedral arrangement of electron pairs, with the two hydrogen atoms occupying two of the corners.

Bawaries are traditional stepwells used for water harvesting and storage, commonly found in regions like Madhya Pradesh and Uttar Pradesh.

Plankton's are passively drifting or floating organisms. Most of these minute organisms, plankton includes photosynthesizing organisms as well as heterotrophic organisms.

The biome occurs in equatorial or sub equatorial regions where both rainfall and warmth are abundant Rainfall is above 140 cm/yr usually between 200-500 cm/yr. It may be upto 1000 cm. Rain occurs through major parts of the year.

Matching rainfall patterns to vegetation: Moderate/heavy year-round supports evergreen forests (3); 7-8 months supports deciduous forests (4); winter rain supports grasslands (2); summer rain supports scrub (1).

Floods are natural disasters caused by excessive and prolonged rainfall that exceeds the drainage capacity of the land.

Water vapor is consistently the most abundant gas released during volcanic eruptions, often accounting for more than 60% of the total gas emission.

Water is essential for all living beings (human, animal and plant) for various
metabolic reactions. They gain water not on;y through the action of drinking but also from the food they eat.

The average annual rainfall in India is widely cited as approximately 105 cm to 110 cm, making 105 cm the most accurate choice among the options.