QJEEM04Ch4404: JEE Main 2004 Chemistry - Class 11 JEEM04Ch4404 Solution: To neutralise completely 20 mL of 0.1 M aqueous solution of…

H₃PO₃ + 2KOH $\to$ K₂HPO₃ + 2H₂O

Let the volume of KOH solution is = V mL = ${V \over {1000}}$ litre

Volume of H₃PO₃ = 20 mL = ${{20} \over {1000}}$ litre

No of moles of H₃PO₃ present = ${{20} \over {1000}} \times 0.1$

No of moles of KOH present = ${V \over {1000}} \times 0.1$

Stoichiometric coefficient of H₃PO₃ = 1

Stoichiometric coefficient of KOH = 2

$\therefore$ ${{{{20} \over {1000}} \times 0.1} \over 1}$ = ${{{V \over {1000}} \times 0.1} \over 2}$

$\Rightarrow$ V = 40 mL