Question

Which among the following salts turns red litmus blue in its aqueous solution?

• A. $CH_{3}COONa$
• B. $CuCl_{2}$
• C. $KCl$
• D. $NaCl$

Hint:

Salt of Strong Base + Weak Acid = Basic solution (pH > 7).

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
Turning red litmus blue indicates a basic solution (\( \text{pH} > 7 \)). This happens when a salt of a strong base and a weak acid undergoes hydrolysis.

Step 3: Detailed Explanation:
(A) \( \text{CH}_3\text{COONa} \): Formed from a weak acid (\( \text{CH}_3\text{COOH} \)) and a strong base (\( \text{NaOH} \)). It undergoes anionic hydrolysis to produce \( \text{OH}^- \) ions, making the solution basic.
(B) \( \text{CuCl}_2 \): Formed from a weak base (\( \text{Cu(OH)}_2 \)) and a strong acid (\( \text{HCl} \)). Solution is acidic.
(C) \( \text{KCl} \): Strong base + Strong acid. Solution is neutral.
(D) \( \text{NaCl} \): Strong base + Strong acid. Solution is neutral.

Step 4: Final Answer:
\( \text{CH}_3\text{COONa} \) turns red litmus blue.