Potassium chloride is added to water and stirred. A salt solution is obtained which is then boiled leaving behind a residue

(a) Is the above change physical or chemical?

(b) Name the residue which remains behind after the salt solution is boiled.

(c) Is the change reversible or not reversible?

(d) Are the composition and properties of the original substance altered.

(e) Give a reason why the above experimentation would not be possible, if calcium carbonate is taken, in place of potassium chloride.

Give a reason why —

(a) Heating a platinum wire is a reversible change but, heating a magnesium wire is an irreversible change.

(b) Addition of zinc nitrate to water is a physical change but, addition of zinc to dilute nitric acid is a chemical change.

(c) Rusting of iron is a chemical change but, magnetization of iron is a physical change.

Select the correct answer from the choice in bracket to complete each sentence:

1. A change in which a substance retains its identity is a …………… [physical/chemical] change.

2. Matter is added or removed during a …………… [chemical/physical] change.

3. Energy required for completion of a physical change is …………… [released/absorbed] when the change is reversed.

4. Dissolution of lead nitrate in water is deemed as a …………… [physical/chemical] change.

5. A change in which matter undergoes a change but the total mass of substance is unaltered is a …………… [physical/chemical] change.

State which of the following 1 to 5 pertain to —

A: Physical Change

B: Chemical change

1. Sublimation.

2. Fermentation.

3. Liquefaction or condensation.

4. Magnetization.

5. Respiration.