A sample of $MnSO_4.4H_2O$ is heated in air to give $Mn_3O_4$.The residue $Mn_3O_4$ is dissolved in 100ml of $N/10$ $FeSO_4$ containing $H_2SO_4$.The solution reacts completely with 50ml of $KMnO_4$.25ml of this $KMnO_4$ requires 30ml of N/10 $FeSO_4$ for complete oxidation.Determine the amount of $MnSO_4.4H_2O$ is the sample

Question

$(1)\;2.5g\qquad(b)\;1.5g\qquad(c)\;1.338g\qquad(d)\;1g$