Question

Identify the increasing order of boiling points for the compounds stated below.
(A) n-Propyl alcohol
(B) n-Butyl alcohol
(C) Isopropyl alcohol
(D) Isobutyl alcohol

• A. \((A)\lt (B)\lt (C)\lt (D)\).
• B. \((C)\lt (A)\lt (D)\lt (B)\).
• C. \((B)\lt (D)\lt (A)\lt (C)\).
• D. \((C)\lt (A)\lt (B)\lt (D)\).

Hint:

Boiling point rises with molar mass and falls with branching.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept
Boiling point increases with the number of carbon atoms and decreases with branching because branching reduces the surface area and van der Waals forces.

Step 2: Propyl Alcohols
n-Propyl alcohol (A) has a higher boiling point than isopropyl alcohol (C), because C is branched.
So \(C<A\).

Step 3: Butyl Alcohols
Isobutyl alcohol (D) is branched, so it boils lower than n-butyl alcohol (B).
So \(D<B\).
Butyl alcohols boil higher than propyl alcohols.

Step 4: Compare the options
The increasing order is \(C<A<D<B\), which is option (B).

Final Answer:
The increasing order is isopropyl, n-propyl, isobutyl, n-butyl. \[ \boxed{\text{(B) }(C)\lt (A)\lt (D)\lt (B)} \]