Importance of Salts and Air Dissolved in Water

Q.

Write a disadvantage of hard water.

Q.

State the importance of the solubility of $C{O}_{2}and{O}_2$ in water.

Q.

What are stalagmites and stalactites. How are they formed ?

Q.

What is the importance of dissolved salts in water?

Q.

Which of the following options do not contain dissolved solids?

1. Tap water

2. Distilled water

3. River water

4. Rainwater

Q. Volume of CO2 obtained at STP by the thermal decompostion of 50 g CaCO3 is (CaCO3 -> CaO + CO2) 1- 22.4 L 2- 2.24 L 3- 5.6 L 4- 11.2 L

Q. What are stalagmites and stalactites? How are they formed?

Q.

Soft water is free from ———

Q. What is the function -The tap at the base of a burette

Q.

Write one advantage of soft water.

Q.

Choose the correct statement(s).

1. Pure water changes the colour of blue litmus to red.

2. Pure water changes the colour of red litmus to blue.

3. Water has dissolved oxygen.

4. Electrolysis of water produces hydrogen and oxygen.

Q.

What is the importance of dissolved salts in water?

Q.

Why are concentric circles formed on the surface of a watch glass after water is evaporated from it?

1. Water does not completely evaporate when left on a watch glass.

2. Water contains dissolved salts that are left behind in concentric circles after evaporation.

3. Water evaporates and condenses on the watch glass to form concentric circles.

4. Water evaporates in a circular fashion.