names the process which takes place when a red litmus paper turns white when dropped into chlorine water​

Chlorine gas bleaches the damp litmus (red or blue). Bleaching is an oxidation process.

Explanation:

Chlorine gas bleaches the damp litmus (red or blue). Bleaching is an oxidation process. If you are considering the colour change only - refer to it as bleaching. If you are considering the reaction mechanism and how the chemicals which provide the colour are changed, then refer to it as oxidation.

Explanation:

yes definetly because you are using energy

it is the most commonly accepted one