The correct options are
A Oxidise 0.5 mol of Fe(2+)
B Oxidise 0.166 mol of FeC2O4
C Oxidise 0.25 mol of C2O(2−)4
In acidic medium, +7MnO−4→+2Mn ; ΔO.N.=5
no. of eq.=0.1×5=0.5 eq.
a) 0.5 mol of Fe(2+)
Fe(2+)→Fe(3+)+e− ; ΔO.N.=1
no. of eq.=0.5 eq.
b) 0.166 mol of FeC2O4
Fe(2+)→Fe(3+)+e− ; ΔO.N.=1
+3C2O(2−)4→2+4CO2+2e− ; ΔO.N.=2
Total ΔO.N.=3
no. of eq.=0.5 eq.
c) 0.25 mol of C2O(2−)4
+3C2O(2−)4→2+4CO2+2e− ; ΔO.N.=2
no. of eq.=0.5 eq.
d) 0.083 mol of Cr2O(2−)7
+6Cr2O(2−)7→2+3Cr ; ΔO.N.=6
Here Cr is in its highest oxidation state so can not be oxidised further.