$13.$ To produce soda ash, $\_($a$)\_$ reacts with $\_($b$)\_$ in the presence of $\_($c$)\_$ to form sodium bicarbonate.

$-$ a$)$ Sodium chloride

$-$ b$)$ Carbon dioxide

$-$ c$)$ Ammonia

$-$ Options:

$-$ i$)$ Sodium hydroxide, Hydrogen, Oxygen

$-$ ii$)$ Sodium chloride, Carbon dioxide, Ammonia

$-$ iii$)$ Sodium sulfate, Carbon monoxide, Water

$14.$ In the mercury cell process, $\_($a$)\_$ is used as the cathode, $\_($b$)\_$ is produced at the anode, and $\_($c$)\_$ is formed in the cell.

$-$ a$)$ Mercury

$-$ b$)$ Chlorine gas

$-$ c$)$ Sodium amalgam

$-$ Options:

$-$ i$)$ Graphite, Hydrogen gas, Sodium chloride

$-$ ii$)$ Mercury, Chlorine gas, Sodium amalgam

$-$ iii$)$ Platinum, Oxygen gas, Sodium hydroxide