ce chemistry

1.5 M hydrochloric acid contains 1.5 moles of hydrochloric acid in 1000 cm^3 of solution.
Molar mass of hydrochloric acid = 1 + 35.45 = 36.45
(atomic mass of H = 1 and atomic mass of Cl = 35.45)


The mass of 1.5 M hydrochloric acid (pure HCl) in 1000 cm^3 of solution 
= 1.5 x 36.45 = 54.675 g

The mass of 1000 cm^3 of solution = density x vol. = 1026 x 1000 = 1026 g
 
Percentage by mass of hydrogen chloride in 1000 cm^3 of solution
= mass of HCl/mass of solution x 100% =54.675 g/1026 g x 100% = 5.33%
 
(Note: That means 1000 cm^3 of solution contains 54.675 g of HCl and (1026 - 54.675 = 971.325) g of water)
 
5.33% is the answer to the question..

1.5M HCl
= 1 mol HCl/1000cm^3 HCl
= 1 mol HCl/1026 g
molar mass of HCl = 1+35 = 36g/mol
so percentage by mass
= 36/1026 * 100%
= 3.51%