Match the following reactions with their mechanisms:
$(A)$ $CH_3CH_2CH_2I \xrightarrow{aq. KOH}$
$(B)$ $(CH_3)_3CCl \xrightarrow{H_2O}$
$(I)$ $S_N1$
$(II)$ $E_2$
$(III)$ $S_N2$
$(IV)$ $E_1$

What is the product $P$ obtained in the following reaction? $CH_3CH_2Br + AgCN_{(alc)} \rightarrow P$

An 'Assertion' $(A)$ and a 'Reason' $(R)$ are given below. Choose the correct answer from the following options.
Assertion $(A)$: Vinyl halides do not undergo nucleophilic substitution easily.
Reason $(R)$: Even though the intermediate carbocation is stabilized by loosely held $p-$ electrons,the cleavage is difficult because of strong bonding.

Arrange the following compounds in order of decreasing rate of hydrolysis for $S_{N}1$ reaction:
$(I) \ C_6H_5-CH_2-Br$
$(II) \ p-CH_3-C_6H_4-CH_2-Br$
$(III) \ p-CH_3CH_2-C_6H_4-CH_2-Br$
$(IV) \ p-(CH_3)_2CH-C_6H_4-CH_2-Br$

$ . . . . . . $ compound is slowly oxidized by air in the presence of light to an extremely poisonous gas, carbonyl chloride.

Product $(A)$ is :