Arrange the following compounds in the increasing order of their boiling points: I. CH3CH2CH2CHO II. CH3CH2CH2CH2OH III. C2H5—O—C2H5 IV. CH3CH2CH2CH2CH3

Question

Arrange the following compounds in the increasing order of their boiling points: I. CH3CH2CH2CHO II. CH3CH2CH2CH2OH III. C2H5—O—C2H5 IV. CH3CH2CH2CH2CH3 (A) I < III < II < IV (B) III < IV < I < II (C) III < II < IV < I (D) IV < III < II < I

Tardigrade Admin · Accepted Answer

The molecular masses of these compounds are

C H_{3} C H_{2} C H_{2} C H O (72), C H_{3} C H_{2} C H_{2} C H_{2} O H (74)

,

C_{2} H_{5} O C_{2} H_{5} (74), C H_{3} C H_{2} C H_{2} C H_{2} C H_{3} (72)

.

Since, only butan-1-ol undergoes extensive intermolecular

H

-bonding therefore its boiling point is the highest. Butanal is more polar than ethoxy ethane, therefore, dipole-dipole interaction in butanal is stronger than that of ethoxy ethane. The van der Waal's forces of attraction between

C_{2} H_{5} O C_{2} H_{5}

are slightly lower than those between molecules of

n

-pentane. Hence, boiling point of

n

-pentane is slightly
higher than that of

C_{2} H_{5} O C_{2} H_{5}

. Thus, the overall increasing order of boiling point is

C_{2} H_{5} O C_{2} H_{5} < C H_{3} C H_{2} C H_{2} C H_{2} C H_{3}

< C H_{3} C H_{2} C H_{2} C H O < C H_{3} C H_{2} C H_{2} C H_{2} O H

Q. Arrange the following compounds in the increasing order of their boiling points : I. CH3​CH2​CH2​CHO II. CH3​CH2​CH2​CH2​OH III. C2​H5​—O—C2​H5​ IV. CH3​CH2​CH2​CH2​CH3​

I < III < II < IV

III < IV < I < II

III < II < IV < I

IV < III < II < I

Q. Arrange the following compounds in the increasing order of their boiling points :
I. $C H_{3} C H_{2} C H_{2} C H O$
II. $C H_{3} C H_{2} C H_{2} C H_{2} O H$
III. $C_{2} H_{5} — O — C_{2} H_{5}$
IV. $C H_{3} C H_{2} C H_{2} C H_{2} C H_{3}$