[ આપેલ : પરમાણુ ક્માંક : $\mathrm{C}: 6, \mathrm{Na}: 11, \mathrm{O}: 8, \mathrm{Fe}: 26, \mathrm{Cr}: 24]$
$8 \mathrm{Na}_2 \mathrm{CrO}_4+2 \mathrm{Fe}_2 \mathrm{O}_3+8 \mathrm{CO}_2$
$\mathrm{~A} \quad \text { B }$
Spin only magnetic moment
$\text { For } \mathrm{Na}_2 \mathrm{CrO}_4 \mu_{\mathrm{B}}=0$
$\text { For } \mathrm{Fe}_2 \mathrm{O}_3 \mu_{\mathrm{B}}=5.9$
$\quad \text { sum }=5.9$