In the electrolysis of water:
(i) Name the gas collected at the cathode and anode respectively .
(ii) Why is the volume of one gas collected at one electrode is double than that at the other ? Name this gas .
(iii) How will you test the evolved gases?

Explanation

(i) At Cathode : hydrogen gas `(H_(2))`
At Anode: oxygen gas `(O_(2))`
(ii) Since, `2H_(2)O overset ("Electric current ")rarr 2H_(2)+O_(2)`
2 molecules of `H_(2)O`, so the volume of `H_(2)` liberated is double that of `O_(2)`
(iii) When a burning splinter is brought near the mouth of the liberated gases, the burning splinter extinguishes near the `H_(2)` gas while the burning splinter keeps burning more near the `O_(2)` gas.