Halogens are coloured and the colour deepens on moving down in the group from fluorine to iodine.
This is due to absorption of energy from visible light which results in excitation of the outer electron.
Give balanced equations for the following reaction:
Acetic acid reacts with phosphorous pentachloride.
Give one chemical test each to distinguish between the following pairs of compounds:
(1) Ethanol and acetic acid
(2) Acetaldehyde and benzaldehyde