Which of the following alcohols on dehydration with conc. `H_(2)SO_(4)` give but-2-ene?

Options

A. 2-Methylpropan-2-ol
B. Butan-1-o
C. 2-Methylpropan-1-ol
D. Butan-2-ol

Answer

B, D

Explanation

`CH_(3)underset(OH)underset(|)overset(CH_(3))overset(|)C CH_(3)overset(H^(+))toCH_(3)-underset(+)overset(CH_(3))overset(|)C-CH_(3)tounderset("2-Methylpropene")(CH_(3))-overset(CH_(3))overset(|)C=CH_(2)`
`CH_(3)CH_(2)CH_(2)CH_(2)OHoverset(H^(+))toCH_(3)underset((1^(@)))(CH_(2))CH_(2)CH_(2)^(+)overset(H^(-)"shift")toCH_(2)underset((2^(@)))(CH_(2))underset(+)CHCH_(3)toCH_(3)underset("But-2-ene")(CH=CHCH_(3))`
`CH_(3)CH_(2)underset(OH)underset(|)CHCH_(2)OHoverset(H^+)toCH_(3)underset((1^(@)))underset(CH_(3))underset(|)(CH)-CH_(2)^(+)overset(H^(-)"shift")toCH_(3)-underset(CH_(3))underset(|)overset(+)C-CH_(3)toCH_(3)-underset("2-Methylpropene")underset(CH_(3))underset(|)C=CH_(2)`
`CH_(3)CH_(2)underset(OH)CHCH_(3)overset(H^(+))toCH_(3)CH_(2)underset(+)CHCH_(3)toCH_(3)underset("But-2-ene")(CH)=CHCH_(3)`