A yellow solution of potassium chromate turns orange on acidification with dilute H2SO4 to give X. In acidic medium X oxidises Fe^2+ to Fe^3+, and the chromium in X is reduced to the ion Y. The spin-only magnetic moment of Y is

JEE Advanced levelSingle correct optionDifficulty 3 of 3df036

A yellow solution of potassium chromate turns orange on acidification with dilute $H X_{2} SO X_{4}$ to give X. In acidic medium X oxidises $Fe X^{2 +}$ to $Fe X^{3 +}$ , and the chromium in X is reduced to the ion Y. The spin-only magnetic moment of Y is

Acidification gives dichromate:

2 CrO X_{4} X^{2 -} + 2 H X^{+} Cr X_{2} O X_{7} X^{2 -} + H X_{2} O

. Then

Cr X_{2} O X_{7} X^{2 -} + 6 Fe X^{2 +} + 14 H X^{+} 2 Cr X^{3 +} + 6 Fe X^{3 +} + 7 H X_{2} O

, so Y is

Cr X^{3 +}

(

3 d^{3}

, 3 unpaired electrons).

μ = 15 = 3.87 BM

; the value 0 would belong to X (Cr +6,

d^{0}