Which’ of the following is NOT a polar protic solvent? A acetone B. acetic acid C methanol D.water
The Correct Answer and Explanation is:
The correct answer is A. Acetone.
Explanation:
A polar protic solvent is one that has both a significant dipole moment (making it polar) and a hydrogen atom attached to an electronegative atom (typically oxygen or nitrogen) capable of forming hydrogen bonds. In a polar protic solvent, the hydrogen can participate in hydrogen bonding with other molecules or ions.
Now, let’s break down the options:
- Acetone (C₃H₆O): Acetone is a polar solvent because of its highly electronegative oxygen atom, but it does not have a hydrogen atom attached to an electronegative atom capable of hydrogen bonding. The hydrogen atoms in acetone are attached to carbon atoms, which do not participate in hydrogen bonding. Therefore, acetone is a polar aprotic solvent.
- Acetic acid (CH₃COOH): Acetic acid is a polar protic solvent because it has an -OH group (hydroxyl) capable of hydrogen bonding. The hydrogen in the -OH group can form hydrogen bonds with other molecules, and the oxygen atom provides the polarity.
- Methanol (CH₃OH): Methanol is another polar protic solvent. It contains an -OH group that can participate in hydrogen bonding, making it capable of donating hydrogen bonds.
- Water (H₂O): Water is one of the most common polar protic solvents. It has two -OH groups capable of forming hydrogen bonds with other molecules, and its polarity is very high due to the large difference in electronegativity between oxygen and hydrogen.
In conclusion, acetone is not a polar protic solvent because it lacks a hydrogen atom attached to an electronegative atom, which is crucial for hydrogen bonding. It is classified as a polar aprotic solvent instead.
