Question
Number of moles of $$MnO_4^ - $$ required to oxidise one mole of ferrous oxalate completely in acidic medium will be
A.
$$0.6{\text{ }}mole$$
B.
$$0.4{\text{ }}mole$$
C.
$$7.5{\text{ }}moles$$
D.
$$0.2{\text{ }}mole$$
Answer :
$$0.4{\text{ }}mole$$
Solution :
In acidic medium $$MnO_4^ - $$ oxidises ferrous oxalate as follows :
$$2\,MnO_4^ - + 5{C_2}O_4^{2 - } + 16{H^ + } \to 2M{n^{2 + }} + 10C{O_2} + 8{H_2}O$$
$$\because \,5\,moles$$ of oxalate ions are oxidised by $$2\,moles$$ of $$MnO_4^ - .$$
$$\therefore \,\,1\,mole$$ of oxalate ion is oxidised by
$$\eqalign{
& = \frac{2}{5}mole\,{\text{of}}\,MnO_4^ - \cr
& = 0.4\,mole\,{\text{of}}\,MnO_4^ - \cr} $$