Answer the following questions: a) Identify X and Y. b) Name the processes in S and R. c) State two uses of sodium carbonate. d) Name the indicator and state the nature of the solution.

Here are the answers to your questions:

12.

a) Name the substances labelled:
X: Carbon(IV) oxide ($\text{CO}_2$)
Y: Ammonium chloride ($\text{NH}_4\text{Cl}$)

b) Name the process that takes place in:
S: Thermal decomposition (or Calcination)
R: Carbonation

c) State 2 uses of sodium carbonate:

• Manufacture of glass.
• Used as a water softener.
• Manufacture of soaps and detergents.

13.

a) Name the indicator.
Universal indicator

b) State the nature of the solution.
Acidic