Consider the reaction, $\mathrm{C}+2{\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{CO}}_2+2{\mathrm{SO}}_2+2{\mathrm{H}}_2\mathrm{O} ;$ Equivalent weight of carbon and sulphuric acid are respectively 

$\mathrm{C} + {\mathrm{H}}_2{\mathrm{SO}}_4 \to {\mathrm{CO}}_2 + {\mathrm{SO}}_2 +{\mathrm{H}}_2\mathrm{O}$

Increase in oxidation number of 'C' = 4

Decrease in oxidation number of 'S' of sulphuric acid = 2

Equivalent weight of carbon= $\frac{12}{4}=3 ;$

Equivalent weight of sulphuric acid= $\frac{98}{2}=49 ;$