Which of the following alcohols will yield the corresponding alkyl chloride on reaction with concentrated HCl at room temperature?

1. 2.
3. 4.
Hint: The rate of reaction totally depends on the stability of carbocation

When alcohols react with conc. HCl at 25 oC then the product which is formed is alkyl chloride.
The rate of reaction totally depends on the stability of carbocation
In step 1, carbocation as an intermediate formation will occur which is attacked by nucleophiles in step 2.

The tendency of nucleophilic attack on carbocation will increase as the stability of carbocation will increase.

Compound d will involve the generation of tertiary carbocation which is the most stable among all other given substate's carbocation, hence here rate of reaction with HCl is maximum. 

The compound in the first option will generate primary carbocation, the compound in the second option will generate secondary carbocation,  the compound in the third option will generate primary carbocation and the compound in the fourth option will generate tertiary carbocation. A primary and secondary carbocation is unstable did not form alkyl chloride with HCl.

Hence, tertiary carbocation is the most stable. Hence, it will yield alkyl chloride on reaction with concentrated HCl. The reaction is as follows: