Question

Calculate the equivalent weight of H₂SO₄.

Answer 1

1. The equivalent mass which is also known as gram equivalent mass is the mass which will combine or displaces a fixed quantity of another substance.
2. Equivalent mass = $\frac{\mathrm{Molar}\mathrm{mass}}{\mathrm{n}-\mathrm{factor}\mathrm{of}\mathrm{acid}}$
3. N-factor of acid is the number of H⁺ions released by an acid.
4. In sulphuric acid, N-factor is 2.
5. Mass of 2 hydrogen atoms: 1
6. Mass of sulphur: 32
7. Mass of oxygen atom: 1
8. $\mathrm{Molar}\mathrm{mass}\mathrm{of}\mathrm{sulphuric}\mathrm{acid}\left({\mathrm{H}}_2{\mathrm{SO}}_4\right)=\mathrm{Mass}\mathrm{of}2\mathrm{hydrogen}\mathrm{atoms}+\mathrm{Mass}\mathrm{of}\mathrm{sulphur}+\mathrm{Mass}\mathrm{of}4\mathrm{oxygen}\mathrm{atom}.$
9. = $2\left(1\right)+32+4\left(16\right)$

= $98\mathrm{u}$

10. Equivalent mass = $\frac{\mathrm{Molar}\mathrm{mass}}{\mathrm{n}-\mathrm{factor}\mathrm{of}\mathrm{acid}}$

= $\frac{98}{2}$

= $49\mathrm{u}$

The equivalent mass of Sulphuric Acid is 49u or 49 g/mol.