In electrolysis of water: Name the gas collected at cathode and anode

(a) Name the gas collected at cathode and anode respectively.

  • Cathode: Hydrogen gas (Hâ‚‚) Anode: Oxygen gas (Oâ‚‚)

(b) Why is volume of one gas collected at one electrode is double of another?

  • Water is made of two hydrogen atoms and one oxygen atom. When it splits, you get twice as much hydrogen gas (Hâ‚‚) as oxygen gas (Oâ‚‚). The reaction is: 2H2O→2H2+O2

(c) Why is it necessary to add few drops of dil. H2SO4 to water before electrolysis?

  • Pure water doesn’t conduct electricity well. Adding a little sulfuric acid (Hâ‚‚SOâ‚„) makes it easier for electricity to flow, so the electrolysis works better.

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