Question

Conversion but-1-ene to but-2- ene.

Answer 1

Conversion of but-1-ene to but-2-ene is by catalytic isomerisation. But-1-ene undergoes isomerisation to but-2-ene on a nickel catalyst in the presence of hydrogen atoms.
To carrc out this process, we add hydrogen bromide to but-1-ene to get
CH3CH2CHBRCH3. We then add alcoholic KOH to get but-2-ene.
Find more details in the image below.

Answer 2

Explanation :

There are two steps involved in this conversion :

Step 1 : First but-1-ene react with the hydrogen bromide to give 2-bromobutane. The addition of polar reagent like HBr to unsymmetrical alkenes follows Markovnikov's rule, which states that the negative part of polar reagent adds to that carbon of double bond which has minimum number of hydrogen.

Step 2 : By the dehydrohalogentaion, the 2-bromobutane react with the alcoholic KOH  to give but-2- ene as a product.

The reaction conversion are shown below.