Molecular weight of NaOH=40 2.5 litre of 1M‌NaOH solution contain 40×2.5g‌of‌NaOH 3 litre of 0.5M‌NaOH solution contain 40×0.5×3g of NaOH If these two solutions are mixed, the volume of the resultant solution =(2.5+3)=5.5 litre. 5.5 litre of the resultant solution contain 40(2.5+1.5)g of NaOH 1 litre of the resultant solution contain
40×4
5.5
g of NaOH=
40×4
5.5×40
‌mole of NaOH The molarity of the resultant solution=0.727≈0.73M