calculate the molarity of 20% sulfuric acid solution with a specific gravity of 1.96

Answer 1

Molarity = moles solute per liter solution

Let us assume we have 1 L of solution

Find the moles of sulfuric acid and then we'll know the molarity.

1 L x 1000 ml / L x 1.96 g / ml = 1960 g of solution

20% of that is sulfuric acid

20% x 1960 g = 392 g sulfuric acid

molar mass H2SO4 = 98 g / mol

moles H2SO4 = 392 g x 1 mol / 98.1 g = 3.996 moles

Molarity of H2SO4 = 3.996 mol / L = 3.996 M = 4.0 M (2 sig. figs.)