Observe the following diagram and answer the questions that follow:
$(i)$ Identify the gases evolved at anode and cathode.
$(ii)$ Why are the amounts of gases collected in the two test tubes not of the same volume?
$(iii)$ What type of reaction is this?
$(iv)$ Why should we use salt water?

(N/A) $(i)$ $(a)$ At the anode,oxygen gas is evolved.
$(b)$ At the cathode,hydrogen gas is evolved.
$(ii)$ The amounts of gases collected in the two test tubes are not of the same volume because water $(H_2O)$ consists of hydrogen and oxygen in a molar ratio of $2:1$. Thus,twice as much hydrogen gas is produced compared to oxygen gas.
$(iii)$ This reaction is an electrolytic decomposition reaction.
$(iv)$ Pure water is a poor conductor of electricity. Salt water is used to act as an electrolyte,allowing electricity to pass through the solution to facilitate the decomposition of water.