Question

36.5% HCl has density 1.20g/ml. The molarity and molality are..

Answer 1

36.5% HCl means 36.5 grams HCl in 100grams solution
Mass of HCl = 36.5g
Mass of water = 100-36.5 = 63.5g=0.0635Kg
Moles of HCl = mass/molar mass = 36.5/36.5 = 1
Volume of solution = mass/density = 100/1.20 = 83.33 ml=0.0833L
Now
Molality = moles/ mass of solvent in Kg = 1 moles/0.0635Kg = 15.75m
Molarity = Number of moles/volume of solution in Litre
= 1 moles/ 0.0833 Litre=12M