Question

Assertion :2-Butanol on heating with $H_{2}S{O}_4$ gives 1-butene and 2-butene. Reason: Dehydration of 2-butanol follows Saytzeff rule.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

In the dehydration of secondary and tertiary alcohols, when there is a possibility of the formation of two isomers. The hydrogen atom is preferentially eliminated from the adjacent carbon atom with the fewer number of hydrogen atoms. This is Saytzeff’s rule.

$C{H}_3-C{H}_2-\stackrel{H}{\stackrel{|}{\underset{OH}{\underset{|}{C}}}}-C{H}_3\underset{{10}^{o}C}{\overset{60\%H_{2}S{O}_4}{\to }}C{H}_3\underset{1-butene\left(20\%\right)}{C{H}_{2}CH=}C{H}_2+C{H}_3\underset{2-butene\left(80\%\right)}{CH=CH}C{H}_3$