Question

Arrange the following compounds in the increasing order of polarity: \[ \text{A. } CH_3CH_2OCH_2CH_3 \] \[ \text{B. } CH_3CH_2OH \] \[ \text{C. } CH_3COCH_3 \] \[ \text{D. } CH_3COOH \] Choose the correct answer from the options given below:

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

Hint:

Remember the general order of polarity for common oxygen-containing organic compounds: \[ \text{Ether} \lt \text{Ketone} \lt \text{Alcohol} \lt \text{Carboxylic Acid} \] The presence and strength of hydrogen bonding play a major role in determining molecular polarity.

Answer 1

The Correct Option is A

Step 1: Know what drives polarity here.
Polarity rises with stronger charge separation and especially with the ability to form intermolecular hydrogen bonds. The general order for these oxygen compounds is ether less than ketone less than alcohol less than carboxylic acid.
Step 2: Identify compound A.
\(A = CH_3CH_2OCH_2CH_3\) is diethyl ether. It has C-O dipoles but no O-H bond, so no hydrogen bonding. It is the least polar.
Step 3: Identify compound C.
\(C = CH_3COCH_3\) is acetone. The \(C=O\) group gives a strong dipole, so it is more polar than the ether: \(A < C\).
Step 4: Identify compound B.
\(B = CH_3CH_2OH\) is ethanol. Its O-H bond allows hydrogen bonding, making it more polar than acetone: \(C < B\).
Step 5: Identify compound D.
\(D = CH_3COOH\) is acetic acid, carrying both \(C=O\) and O-H. It hydrogen bonds very strongly and even dimerises, so it is the most polar: \(B < D\).
Step 6: Assemble the increasing order.
Putting the comparisons together gives \(A < C < B < D\).
\[ \boxed{A < C < B < D} \]