Question

How many structural isomeric alkenes on hydrogenation give n pentane?

Answer 1

The answer is in the image. Please comment if unclear.
The total number is 2.

Answer 2

HEY MATE!!

Hydrogenation – meaning, to treat with hydrogen – is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organic compounds...........

HOPE IT HELPS!