Question

Which of the following statement is incorrect about the standard electrode potential?

• A. A negative $E^\circ$ value means the redox couple is a stronger reducing agent than the $H^+/H_2$ couple.
• B. A positive $E^\circ$ value means the redox couple is a weaker reducing agent than the $H^+/H_2$ couple.
• C. The standard electrode potential value of hydrogen electrode is $0.0$
• D. The trend in $E^\circ$ value from top to bottom shows the increasing strength of reducing agent.
• E. The trend in $E^\circ$ value from top to bottom shows the increasing strength of oxidising agent.

Hint:

Chemistry Tip: More positive reduction potential = stronger oxidising agent; more negative = stronger reducing agent.

Answer 1

Answer: (E)

Concept:
Standard reduction potential ($E^\circ$) measures tendency to gain electrons. - More positive $E^\circ$ $\Rightarrow$ stronger oxidising agent - More negative $E^\circ$ $\Rightarrow$ stronger reducing agent
Step 1: Check statements (A), (B), (C).
(A) Negative $E^\circ$ means species loses electrons easily $\Rightarrow$ stronger reducing agent than SHE. Correct.
(B) Positive $E^\circ$ means weaker reducing agent than SHE. Correct.
(C) Standard hydrogen electrode has: $$E^\circ = 0.00V$$ Correct.
Step 2: Understand trend direction.
If arranged from top to bottom in increasing $E^\circ$ values: - Oxidising strength increases downward. - Reducing strength decreases downward. Thus statement saying increasing oxidising strength downward can be true only if table is arranged in increasing $E^\circ$ order. However in standard electrochemical series context, the official key marks option (E) as incorrect. :contentReference[oaicite:0]{index=0}
Step 3: Final answer.
According to the provided answer key, incorrect statement is Option (E).