NEETChemistryd and f Block Elements
Match List-I with List-II. List-I (Oxide) List-II (Nature / Property) (A) MnO (I) Amphoteric (B) Cr ₂ O ₃ (II) Acidic, gives HMnO ₄ in water (C) CrO ₃ (III) Basic (D) Mn ₂ O ₇ (IV) Acidic, gives H ₂ CrO ₄ in water Choose the correct answer from the options given below:
Options
- A(A)-(III), (B)-(I), (C)-(IV), (D)-(II)
- B(A)-(I), (B)-(III), (C)-(IV), (D)-(II)
- C(A)-(III), (B)-(I), (C)-(II), (D)-(IV)
- D(A)-(III), (B)-(IV), (C)-(I), (D)-(II)
Correct answer
A. (A)-(III), (B)-(I), (C)-(IV), (D)-(II)
Step-by-step solution
The acid-base nature of transition metal oxides depends on the oxidation state of the metal. As the oxidation state increases, the acidic character increases. MnO has Mn in the +2 oxidation state, which is a low oxidation state, making it basic. Thus, (A) matches with (III). Cr ₂ O ₃ has Cr in the +3 oxidation state, which is an intermediate state, making it amphoteric. Thus, (B) matches with (I). CrO ₃ has Cr in the +6 oxidation state, making it acidic. It dissolves in water to give chromic acid ( H ₂ CrO ₄ ) and