CHEMISTRY [2 Mark Question Answer]

water pollution - Water pollution is the contamination of water sources by substances which make the water unusable for drinking, cooking, cleaning, swimming, and other activities.
pollutants - include chemicals, trash, bacteria, and parasites. All forms of pollution eventually make their way to water

Most of the farming activities are responsible for water pollution due to excessive use of pesticides and chemical fertilizers, which ultimately leaches in groundwater and drains into surface water bodies—the change in Physio-chemical properties of water due to agricultural activities detriment the aquatic ecosystem

Domestic water pollution is produced by the discharge of domestic sludge containing organic substances and soaps. These substances generally pour into superficial river flows but sometimes reach aquifers. It’s possible to reduce waste water pollution thanks to purification.

It is a complex system that includes many different processes. Liquid water evaporates into water vapor, condenses to form clouds, and precipitates back to earth in the form of rain and snow. Water in different phases moves through the atmosphere (transportation)

It has been estimated that the total number of species of plants and animals living today varies 5 million, but only 1.8 million species have so far been described. Of the total known biodiversity, about 0.5 million species represent plants and the remaining species contribute animals.

When a piece of sodium metal dropped in cold water we observe: Sodium floats on water surface melts forming a silvery globule which darts about the surface of water catches fire and burns with golden yellow flame. Bubbles of hydrogen evolve and solution is soapy, slightly warm (alkaline) hence turns red litmus blue.

(a) a graphic representation of the variation with changing temperature of the solubility of a given substance in a given solvent.
(b) It gives an idea about the ability of a solute to dissolve in water at different temperature. 2. The solubility of a solute at any temperature can be measured

(a) increases with the rise in temperature.– KCl
(b) remains practically unaffected with the rise in temperature–Sodium chloride(NaCl)
(c) decreases with the rise in temperature–alcium hydroxide(Ca(OH)₂) Calcium sulfate(CaSO₄)

(a) It means 14.3 gm of solute can be dissolve in 100 gm of water at 0ºC
(b) three factors which determine the solubility
The size of solute particles, stirring, and temperature, are the three factors that affect the solubility of a solid solute in a solvent

(a) the number of water molecules that combine chemically in definite molecular proportion, with the concerned salt in the crystalline state. This water is responsible for the geometric shape and colour of the crystal
(b) when it comes in contact with water it forms CuSO4. 5H2Owhich is blue in colour. thus when anhydrous CuSO4 is put in a liquid containing moisture it will turn blue. This is how anhydrous CuSO4 is used to detect moisture(water

(a) (i) Increase (ii) Increase
(b) The liquid in the soda bottle is under high pressure. When you open the bottle, the dissolved carbon dioxide is depressurized and wants to rapidly expand. Thus effervescence is seen when a bottle of soda is opened.

(a) Take some water in a glass or metal container like pan and heat it. Just before water begins to boil, you will notice some bubbles at the inner surface of the pan. These bubbles come from the air dissolved in water. This shows that air is dissolved in water
(b) In boiled off air the concentration of nitrogen and oxygen will be less as compared to ordinary air

(a) Take a small quantity of tap water glass on a beaker filled with water when the watch glass is seen in light a number of concentric rings of solid matter are seen. These are deposited of deposits of dissolved salt left after evaporation of tap water
(b) The dissolved impurities in water are salts and minerals. Dissolved salts provide specific taste to water. Salts and minerals are essential for growth and development. They supply the essential minerals needed by our body.

physical properties of water.

• Density.
• Melting point.
• Boiling point.
• Hardness.
• Electrical conductivity.