Question

Concentrated HCL has a specific gravity of 1.185 and is 36.5% HCL by weight. How many milliliters (measured at STP) of dry hydrogen chloride gas are dissolved in 1.00 L of the concentrated acid?

Answer 1

Ans:- Specific gravity is a dimensionless unit defined as the ratio of density of substance to density of water at specified temperature (normally at 4 C).

density of water is normally 1.0 .

therefore,specific gravity =1.185

now 36.5% HCl by weight means 36.5 g per 100 g of solution.

density=mass/volume

volume of 100 g of solution=100/1.185=84.38 ml of solution= .08438 Litre of solution.

therefore .08438 litre solution contains 36.5 g HCl.

so 1 L contain= 36.5/.08438 =432.56 g oh HCl.

no of moles= 432.56/36.5= 11.85 moles

1 mole of ideal gasoccupies 22.4 l at STP.

so 11.85 moles= 265.46 L =2.65 * 10⁵ of Dry HCl in 1 L of conc HCl