a. Compound A (molecular formula `C_(5)H_(10)`) gives only one monochorinated product. Write the structure of Compound A.
b. How many monochlorinated products can be obatined from all the isomeric alkanes having the formula `C_(5)H_(10)` (excluding steroisomers) ?

Explanation

a. `C_(5)H_(10)` has `1^(@)` of unsaturation. It should have either one double bond of should be a cyclic compound. If it has one doble, then it should give many monochlorinated products. So, it is a cyclic compound. Thus, it should be cylopentane.
will give only one monochloro product, while other cyclic isomers will give serveral products.
So,
b. The different isomers can be
i. ii. iii.
iv. v.
i.
ii.
iii.
iv.
v.
Therefore, total number of isomers `=1+4+3+4+2 =14` (excluding stereoisomers).