The molecular mass of sulphuric acid is 98. If 49 g of the acid is dissolved in water to make one litre of solution, what will be the strength of the acid?
[amp_mcq option1=”Two normal” option2=”One normal” option3=”0·5 normal” option4=”Four normal” correct=”option2″]
This question was previously asked in
UPSC CDS-1 – 2017
Number of moles of H₂SO₄ = Mass / Molar mass = 49 g / 98 g/mol = 0.5 mol.
The molarity of the solution is Moles / Volume (L) = 0.5 mol / 1 L = 0.5 M.
Normality (N) is defined as Molarity (M) multiplied by the n-factor (equivalents per mole). For sulfuric acid acting as an acid, it has two acidic protons (H⁺) that can be donated, so its n-factor is 2.
Normality = Molarity × n-factor = 0.5 M × 2 = 1 N.
The strength of the acid solution is one normal.