1 mole of 02consumes→2 moles of Mn+2
8mg consumes :-
32 g makes→ 1 mole of O2
1gmakes→132 moles of O2
8×10−3 g makes →1×8×10−3moles of O232
=0.25×10−3moles
1 mole of O2 consumes 2 mole of Mn+2
0.25×10−3 moles will → consume 2×0.25×10−3
=5×10−4 moles
Hence, option A is correct.