$15.$ During the production of caustic soda using a diaphragm cell, $\_($a$)\_$ passes through the diaphragm to the cathode compartment, producing $\_($b$)\_$ and $\_($c$)\_.$

$-$ a$)$ Sodium ions

$-$ b$)$ Sodium hydroxide

$-$ c$)$ Hydrogen gas

$-$ Options:

$-$ i$)$ Chloride ions, Hydrochloric acid, Water

$-$ ii$)$ Sodium ions, Sodium hydroxide, Hydrogen gas

$-$ iii$)$ Calcium ions, Calcium hydroxide, Chlorine gas

$16.$ Bleaching powder is commonly produced by the reaction of $\_($a$)\_$ with chlorine gas, resulting in the formation of $\_($b$)\_$ and $\_($c$)\_.$

$-$ a$)$ Calcium hydroxide

$-$ b$)$ Calcium hypochlorite

$-$ c$)$ Calcium chloride

$-$ Options:

$-$ i$)$ Sodium hydroxide, Sodium chloride, Calcium carbonate

$-$ ii$)$ Calcium hydroxide, Calcium hypochlorite, Calcium chloride

$-$ iii$)$ Magnesium hydroxide, Magnesium chloride, Calcium carbonate