Question

Consider the following half cell reactions with corresponding standard reduction potentials. \(Cl_{2(g)} + 2e^{-} \rightarrow 2Cl^{-}_{(aq)}, E^{\circ} = +1.36\) V \(Al^{+3}_{(aq)} + 3e^{-} \rightarrow Al_{(s)}, E^{\circ} = -1.66\) V \(Na^{+}_{(aq)} + e^{-} \rightarrow Na_{(s)}, E^{\circ} = -2.71\) V \(Cu^{+2}_{(aq)} + 2e^{-} \rightarrow Cu_{(s)}, E^{\circ} = +0.377\) V The strongest oxidising and reducing agents respectively are -

• A. \(Al^{+3}\) and \(Na^{+}\)
• B. \(Na^{+}\) and \(Cl_2\)
• C. \(Cl_2\) and Na
• D. \(Cu^{+2}\) and \(Al^{+3}\)

Hint:

The strongest oxidising agent has the highest reduction potential, and the strongest reducing agent has the lowest.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept
A higher (more positive) \(E^{\circ}\) means the species is more easily reduced, so it is a stronger oxidising agent.
A lower (more negative) \(E^{\circ}\) means the reduced form is a stronger reducing agent.

Step 2: Compare the values
\(E^{\circ}\) of \(\text{Cl}_2/\text{Cl}^{-} = +1.36\) V is the highest, so \(\text{Cl}_2\) is the strongest oxidising agent.
\(\text{Na}^{+}/\text{Na} = -2.71\) V is the lowest, so Na is the strongest reducing agent.

Step 3: Match
The pair is \(\text{Cl}_2\) and Na, option (C).

Final Answer:
The strongest oxidising agent is chlorine and the strongest reducing agent is sodium. \[ \boxed{\text{(C) }\text{Cl}_2\text{ and Na}} \]