JEE MainChemistryd and f Block Elements
Consider the following statements regarding the properties of chromates and dichromates: (A) Sodium dichromate is more soluble in water than potassium dichromate. (B) Potassium dichromate is highly hygroscopic and readily absorbs moisture from the air. (C) In an acidic medium, the oxidation state of chromium increases when chromate changes to dichromate. (D) Chromate and dichromate ions are interconvertible in aqueou
Options
- A(A), (B) and (D) only
- B(A) and (D) only
- C(A), (C) and (D) only
- D(C) and (D) only
Correct answer
B. (A) and (D) only
Step-by-step solution
Statement (A) is correct: Sodium salts are generally more soluble in water than their corresponding potassium salts. Na ₂ Cr ₂ O ₇ is much more soluble than K ₂ Cr ₂ O ₇ . Statement (B) is incorrect: Sodium dichromate ( Na ₂ Cr ₂ O ₇ ) is hygroscopic, whereas potassium dichromate ( K ₂ Cr ₂ O ₇ ) is not hygroscopic, which is why the latter is preferred as a primary standard in volumetric analysis. Statement (C) is incorrect: The oxidation state of chromium in both chromate ( CrO ₄²⁻ ) and dichromate ( Cr ₂ O ₇²⁻ )