Observed and calculated values for the standard electrode potentials ($M^{2+}→ M$) are shown in the figure above. Based on the data shown, which of the following statements are true?

(A) Cu is not able to liberate $H_2$ from acid.
(B) Zn is not able to liberate $H_2$ from acid.
(C) An increase in the sum of the first and second ionization enthalpies leads to less negative E° values.
(D) Only oxidising acids react with $Cu$

Choose the correct answer from the options given below:

(A), (C) and (D) only

The correct answer is Option (1) → (A), (C) and (D) only

Let’s analyze the statements based on standard electrode potentials (E°) and typical metal reactivity:

• (A) Cu is not able to liberate H₂ from acid  True
• Copper has a positive E° (+0.34 V), so it is less reactive than H⁺ and cannot displace H₂ from acids.
• (B) Zn is not able to liberate H₂ from acid  False
• Zinc has a negative E° (−0.76 V), so it can liberate H₂ from acids.
• (C) An increase in the sum of first and second ionization enthalpies leads to less negative E° values  True
• Metals with high ionization enthalpies are harder to oxidize, giving less negative or more positive E°.
• (D) Only oxidising acids react with Cu  True
• Copper reacts only with strong oxidizing acids (like HNO₃, H₂SO₄(conc)), not with dilute non-oxidizing acids.