Question

Which of the following reducing agents liberates hydrogen from dilute acid?

• A. \( {Mn}^{2+} \)
• B. \( {Fe}^{2+} \)
• C. \( {Cr}^{2+} \)
• D. \( {Co}^{2+} \)

Hint:

To identify a reducing agent that liberates hydrogen from dilute acid, look for a metal ion in a lower oxidation state. Chromium(II) (\( {Cr}^{2+} \)) is a well-known reducing agent that can reduce hydrogen ions to hydrogen gas.

Answer 1

The Correct Option is C

\( {Cr}^{2+} \) is a strong reducing agent and can liberate hydrogen from dilute acid. Therefore, the correct answer is \( {Cr}^{2+} \).