Question

A solution is 20% by weight in H2SO4 and has a density of 1.14g/mL. Determines: (a) Molarity of solution b) Molarity of solution

Answer 1

20% by weight means 20 g of H₂SO₄ present in 100g solution.

moles of H₂SO₄ = $\frac{20}{98} moles$

Molarity = no. of moles of solute/vol. of solution

Molarity = $\frac{\frac{20}{98} }{\frac{100}{1000}}$

Molarity = 2.04 M

density of solution is given = 1.14g/mL

so mass of solution = 100*1.14 = 114 g

mass of solvent = 114 - 20 g = 94 g

Molality = no. of moles of solute / mass of solvent

Molality = $\frac{\frac{20}{98} }{\frac{94}{1000}}$

Molality = 2.17 molal