Question

specifically calculate the molarity and molality for hydrogen chloride gas dissolved in pure water, at 298K, to produce a hydrochloric acid solution that is 37.0% HCl and density of solution is 1.19 g/mL

( you have to specific tasks, but how many implied tasks are there. Problem requires...)

- Find molarity for HCl(aq)

- Find molality for HCl(aq)

Answer 1

Basis : 100 gm of solution is assumed, mass of HCl is 37% , mass of HCl= 37 gms moles of HCl= mass/molecular weight, Molecular weight of HCl= 36.5 , moles of HCl =37/36.5=1.013moles

Density of the solution = 1.19 g/mol, volume of solution= mas/volume= 100/1.19 ml=84.03ml

Volume of the solution= 84.03/1000 L=0.08403L

Molarity= Moles of HCl/ per liter of solution= 1.013/0.08403=13.44 M

b) Molality = moels of HCl/ kg of water

Amount of water in the solution= 100-37= 63g =63/1000 kg=0.063kg

Molality= moles of HCl/ kg of water= 1.013/0.063=17.93 m