Question

Which among the following is an example of metal–sparingly soluble salt electrode?

• A. \(\mathrm{OH^- (aq)\ | \ O_2(g),\ Pt}\)
• B. \(\mathrm{Cl^- (aq)\ | \ AgCl(s)\ | \ Ag(s)}\)
• C. \(\mathrm{Zn^{2+}(aq)\ | \ Zn(s)}\)
• D. \(\mathrm{Cu^+(aq),\ Cu^{2+}(aq)\ | \ Pt}\)

Hint:

Silver–silver chloride electrode is a common reference electrode based on a sparingly soluble salt.

Answer 1

The Correct Option is B

Step 1: Define metal–sparingly soluble salt electrode.
This type of electrode consists of a metal in contact with a sparingly soluble salt of the same metal and a solution containing a common anion.
Step 2: Analyze the given options.
\(\mathrm{Ag|AgCl|Cl^-}\) is a classic example where silver is in contact with its sparingly soluble salt silver chloride.
\(\mathrm{Zn^{2+}|Zn}\) is a metal–metal ion electrode.
\(\mathrm{Cu^+/Cu^{2+}|Pt}\) is a redox electrode.
\(\mathrm{OH^-|O_2|Pt}\) is a gas electrode.
Step 3: Conclusion.
Hence, the correct example of a metal–sparingly soluble salt electrode is \(\mathrm{Cl^-|AgCl|Ag}\).