An organic compound $A$ $(C_4H_9Cl)$ on reaction with $Na$ in diethyl ether gives a hydrocarbon,which on monochlorination gives only one chloro derivative. $A$ is:

Given below are two statements:
Statement $I$: $(Et)_2N-CH_2CH_2Cl$ will undergo alkaline hydrolysis at a faster rate than $(Et)_2CH-CH_2CH_2Cl$.
Statement $II$: Intramolecular substitution takes place first by involving the lone pair of electrons on nitrogen.
In the light of the above statements,choose the most appropriate answer from the options given below:

Assertion $(A)$: $S_N1$ hydrolysis of optically active $2-$bromooctane results in the formation of $(\pm)-$octan$-2-$ol.
Reason $(R)$: The reaction proceeds through a planar carbocation which can be attacked by the nucleophile from either side.
The correct answer is

The reactivity of ethyl chloride towards nucleophilic substitution is:

Which of the following,on heating with aqueous $KOH$,produces acetaldehyde?

Which one of the following reagents is not suitable for the elimination reaction shown in the image?