The main product in the dehydration of :
`(CH_(3))_(3) C underset(OH)underset(|)(CH)CH_(2)CH_(3)` in the presence of conc. `H_(2)SO_(4)` at `170^(@)C` is :

Options

A. `(CH_(3))_(3) C CH = CHCH_(3)`
B. `(CH_(3))_(2)C = underset(CH_(3))underset(|)(C)CH_(2)CH_(3)`
C. `(CH_(3))_(2)CH underset(CH_(3))underset(|)(C) = CHCH_(3)`
D. `(CH_(3))_(3)C CH_(2)CH = CH_(2)`

Answer

B

Explanation

The intermediate carbocation `(CH_(3))_(3)C - underset(oplus)(CH) - CH_(2) - CH_(2)` undergoes rearrangement by methyl shift to form stable tertiary carbocation as :
`CH_(3) - underset(CH_(3))underset(|)overset(CH_(3))overset(|)(C) - underset(oplus)(CH) - CH_(2) - CH_(3) overset("Rearrangement")harr CH_(3) - underset(oplus)overset(CH_(3))overset(|)(C) - underset(CH_(3))underset(|)(CH) - CH_(2) - CH_(3)`
This carbonium ion loses `H^(+)` to form `(CH_(3))_(2) C = underset(CH_(3))underset(|)(C) - CH_(2) - CH_(3)` as the main product.