The correct option is B 2 mol Ca(OH)2
BaF2(1mol)+H2SO4(2mol)→BaSO4+H2F2+H2SO4(unreacted)
1 2 1 1 1
Acid requires base for neutralisation according to the above reaction:
H2F2=2OH−= 1 mol Ca(OH)2 or 2 mol KOH
HSO4=2OH−= 1 mol Ca(OH)2 or 2 mol KOH
So, this solution will require total 2 mol Ca(OH)2 or 4 mol KOH for neutralisation.