When an alkaline solution of K2CrO4 is treated with 3% H2O2 solution, red brown paramagnetic peroxochromate is obtained as per following equation: 2K2CrO4 + 7H2O2 + 2KOH → 2K3CrO8 + 8H2O The equivalent weight of K2CrO4 for above transformation must be (assuming M is the molar mass of K2CrO4):
Correct answer: B. M
- A. M/16
- B. M
- C. M/12
- D. M/2
Explanation
The equivalent weight of a substance in a reaction is given by its molar mass divided by the n-factor. In this reaction, 2 moles of K2CrO4 are transformed into 2 moles of K3CrO8. The n-factor, which represents the change in oxidation state per formula unit, is 1 for this transformation. Therefore, the equivalent weight of K2CrO4 is equal to its molar mass, M. Option B correctly reflects this. The other options (A, C, and D) do not correctly account for the stoichiometry and n-factor calculation, leading to incorrect equivalent weight values.
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