Q57. The fusion of chromite ore with sodium carbonate in the presence of air leads to the formation of products A and B along with the evolution of $\mathrm { CO } _ { 2 }$. The sum of spin-only magnetic moment values of $A$ and $B$ is $\_\_\_\_$ B.M. (Nearest integer) [Given atomic number : $\mathrm { C } : 6 , \mathrm { Na } : 11 , \mathrm { O } : 8 , \mathrm { Fe } : 26 , \mathrm { Cr } : 24$ ]