Calculate the molarity of 30% H2SO4 solution by mass if density of the solution is 1.19 g cm cube.

30 % H₂SO₄ (by mass) = 30 g H₂SO₄ in 100 ml
 
In 100 ml solution sulphuric acid present = 30 g
In  1 ml solution sulphuric acid present = 30/100 g
In 1000 ml solution sulphuric acid present = (30/100) X 1000 g = 300 g
 
Molecular weight of H₂SO₄ = 1X2 + 32 + 16 X4 = 98
98 g H₂SO₄ = 1 mol
1  g H₂SO₄ = 1/98 mol
300 g H₂SO₄ = (1/98)X300 mol = 3.06 mol (approx)
 
So molarity of the solution is 3.06 M