Question

When will be the acidic character of carboxylic acid higher in following cases ?

• A. Lower \(K_a\) and \(pK_a\) values
• B. Lower \(K_a\) value and higher \(pK_a\) value
• C. Higher \(K_a\) value and lower \(pK_a\) value
• D. Higher \(K_a\) and \(pK_a\) values

Hint:

A stronger acid has a larger \(K_a\) and a smaller \(pK_a\).

Answer 1

The Correct Option is C

Step 1: Use the definition
$pK_a = -\log K_a$.

Step 2: Apply
Stronger acid means bigger $K_a$ and therefore smaller $pK_a$. Option (C).

Final Answer:
A strong acid has high $K_a$ and low $pK_a$, option (C). \[ \boxed{\text{High }K_a,\ \text{low }pK_a} \]