Question

What is the molarity of a 10.6 % by mass glucose (C6H12O6) solution? (The density of the solution is 1.03 g/mL .)

Express your answer in appropriate units.

Answer 1

Basis : 100 gm of solution

Density =1.03 g/ml

Since density= mass/ volume , Volume of solution= mass/ density= 100/1.03 ml =97.08 ml

But 1000ml =1 L and hence 97.08ml =97.08/1000 L=0.097087

Mass of glucose in 100 gms= 10.6%, that is 10.6 gms

Atomic weights : C =12 , H= 1 and O=16

Molecular weight of glucose (C6H12O6)= 6*12+12*1+6*16=180

Moles of glucose = mass/ molecular weight= 10.6/180=0.058889

Molarity = moles of solute ( glucose)/ Litre of solution= 0.05889/0.097087=0.606556 Moles/ L