Question

Ferrous ion changes to X ion on reacting with acidified hydrogen peroxide. The number of d-electrons present in X and its magnetic moment (in BM) are respectively

• A. 6 and 6.93
• B. 5 and 5.92
• C. 5 and 4.9
• D. 4 and 5.92

Answer 1

Answer: (B)

Ferrous ion ( $F{e}^{2+}$ ) changes to ferric ion $F{e}^{3+}$ on reacting with acidified $H_2{O}_2$ as.

$2F{e}^{2+}+H_2{O}_2+2H^{+}\to 2F{e}^{3+}+2H_{2}O$

Electronic configuration of $F{e}^{3+}$ $=1{\text{s}}^{2}2{\text{s}}^{2}2{\text{p}}^{6}3{\text{s}}^{2}3{\text{p}}^{6}3{\text{d}}^5$

Number of $\text{d}$ -electrons = 5

Magnetic moment $=\sqrt{n(n+2)}=\sqrt{5(5+2)}=5.92BM$