Question

Arrange the following compounds in increasing order of boiling point. Propan - 1 - ol, butan - 1 - ol, butan - 2 - ol, pentan - 1 - ol
(a) Propan-1-ol, butan-2-ol, butan - 1 - ol, pentan-1-o|
(b) Propan-1-ol, butan - 1 - ol, butan-2-ol, pentan-1-ol
(c) Propan-1-ol, butan-2-ol, butan-1-ol, pentan-1-ol
(d) Propan-1-ol, butan-1-ol, butan-2-ol, pentan-1-ol

Answer 1

Boiling point increases with increase in the number of carbon atoms because of increase in molecular mass. So, the boiling point of pentan-1-ol is more than that of all other given compounds. Further, among isomeric alcohols, $1^{\circ }$ alcohols have higher boiling points than $2^{\circ }$ alcohols because of higher surface area in $1^{\circ }$ alcohols. Therefore, boiling point increase in the order
Propan-1-ol < butan-2-ol < butan-1-ol < pentan-1-ol.
Here, the correct option is (a).