Question

Certain electric current for half an hour collects \(11.2\,L\) of hydrogen at NTP. Same current passed for one hour deposits how much silver?

• A. \(216\,g\)
• B. \(108\,g\)
• C. \(47\,g\)
• D. \(60\,g\)

Hint:

1 Faraday deposits 1 gram-equivalent.

Answer 1

The Correct Option is A

Concept: Faraday’s laws of electrolysis.

Step 1: Hydrogen moles.
\[ 11.2\,L \Rightarrow 0.5\,mol \, H_2 \]

Step 2: Electrons required.
\[ H_2: 2e^- \Rightarrow 1\,mol\,H_2 = 2F \] \[ 0.5\,mol \Rightarrow 1F \]

Step 3: Time doubled \(\Rightarrow\) charge doubled.
\[ \Rightarrow 2F \]

Step 4: Silver deposition.
\[ Ag^+ + e^- \rightarrow Ag \] \[ 2F \Rightarrow 2\,mol\,Ag = 2 \times 108 = 216\,g \]