Step 1:
In first step when Phenyl Magnesium Bromide (Grignard Reagent) is treated with phosgene it produces Benzoyl Chloride. In this step Grignard reagent act as a nucleophile while phosgene acts as electrophile.
Step 2:
The Benzoyl chloride formed in first step still has an electrophillic carbon, therefore, another grignard reagent (which is present in excess) is added to the carbonyl group and results in the elimination of chloride ion (good leaving group) and formation of Benzophenone.
Step 3:
The benzophenone (ketone) formed in second step contains a carbonyl group with electrophilic carbon. Hence, the grignard reagent is added through nucleophilic addition reaction and forms a tetrahedral intermediate, which upon hydrolysis yields triphenylmethanol (tertiary alcohol). This tertiary alcohol formed can not undergo reaction with grignard reacgent because it does not contain any electrophilic center.</span>
Salt is an ionic compound NaCI. So the salt will dissolve and spread apart and the ions in the salt will move freely, letting electricity to flow freely....!
Hope i helped! If you need anything else ask me!! :)