11Q-1
let the total volume of solution be 100 cm3
density of soltion =0.96gm/cm3
therefore mass of solution = 96 gm
then according to question ethanol =20% by volume ie ethanol=20cm3
so volume of H2O in solution = 80cm3
now we know density of water =1gm/cm3
therefore mass of water in solution = 80gm
so mass of ethanol =16gm
moles of ethanol = 16/46 =8/23=0.348
therefore m(molality)= 0.34880*1000=4.35
now 1000cm3 =1 litre
therefore 100cm3(ie the volume of solution)=0.1 litre
therefore M(molarity)= 0.3480.1=3.48
i hope the answer is right
