Assertion (A): Formic acid is a stronger acid than acetic acid.
Reason (R): Formic acid is an organic acid.
A
Both A and R are true, and R is the correct explanation of A
B
Both A and R are true, but R is NOT a correct explanation of A
C
A is true, but R is false
D
A is false, but R is true
Correct Answer: Option B
Explanation
1. Assertion (A) states that Formic acid is a stronger acid than acetic acid. This is true. Formic acid (HCOOH) has a pKa of about 3.77, while acetic acid (CH3COOH) has a pKa of about 4.76. A lower pKa indicates a stronger acid.
2. Reason (R) states that Formic acid is an organic acid. This is true, as it contains carbon. Acetic acid is also an organic acid.
3. However, the fact that formic acid is an organic acid does not, by itself, explain why it is stronger than acetic acid. The difference in strength is due to the electron-donating effect of the methyl group (CH3) in acetic acid, which destabilizes the acetate anion, making the acid weaker compared to formic acid where hydrogen is attached to the carboxyl group.
4. Therefore, both A and R are true, but R is not the correct explanation of A. Option (B) is the correct answer.