A sample of 12 M concentrated hydrochloric acid has a density 1.2g L ^(-1)Calculated the molality.

A sample of 12 M concentrated hydrochloric acid has a density 1.2g L ^

1.	A sample of 12 M concentrated hydrochloric acid has a density 1.2g L ^(-1)Calculated the molality.
Answer» Solution :Given: Molarity `= 12 MHCl` DENSITY of the solution `=1.2 G L ^(-1)` In 12 M HCL solution, there are 12 moles of HCl in 1 litre of the solution. Molality `= ("No. of moles of solute")/("Mass of solvent (in kg)")` Caculate mass of water (solvent) Mass of 1 litre HCl solution = density `xx` VOLUME `=1.2 GM L ^(-1) xx 100 mL = 1200g` Mass of HCl = No of moles of HCl` xx` molar mass of HCl Mass of water= mass of HCl solution - mass of HCl Mass of water `=1200 - 438 =762 g` Molality `= (12)/(0.762) =15.75m`