Compound A, C8H10, absorbed 3 equivalents of H2 on catalytic hydrogenation over a Pd/C catalyst to give B (C8H16). On ozonolysis, compound A gave, among other things, a ketone which was identified as cyclopentanone. On treatment with NaNH2 in NH3, followed by addition of iodomethane, compound A gave a new hydrocarbon, C (C9H12). Draw the structure of Compound A and Compound B.

Compound A, C8H10, absorbed 3 equivalents of H2 on catalytic hydrogenation over a Pd/C catalyst to give B (C8H16). On ozonolysis, compound A gave, among other things, a ketone which was identified as cyclopentanone. On treatment with NaNH2 in NH3, followed by addition of iodomethane, compound A gave a new hydrocarbon, C (C9H12). Draw the structure of Compound A and Compound B.

Explanation:

The degree of unsaturation in the given compound A  C8H10 is:

DU= (Cn+1)-Hn/2 -Xn/2 +Nn/2

DU=(8+1)-10/2

    =9-5

    =4

So, the given compound has either three double bonds and a ring or four double bonds or four rings.

Given,

compound A C8H10 absorbed three equivalents of H2 on catalytic hydrogenation that means compound A has three double bonds or it has one double bond and one triple bond.

The structure of compounds A, B and C along with the entire reaction is shown below:

it is the most commonly accepted one

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.