Question

Calculate the concentration of an oxalic acid (H2C2O4) solution if it takes 34.0 mL of a 0.200 M NaOH solution to consume the acid in 25.0 mL of the oxalic acid solution. The net ionic equation of the titration reaction is: H₂C₂O4(aq) + 2 OH^– (aq) --> C₂O₄2–(aq) + 2 H₂O(l)

Answer 1

H2C2O4(aq) + 2 OH– (aq)   C2O42–(aq) + 2 H2O(l)

Volume of NaOH solution = 34.0 mL

Molarity of NaOH solution = 0.200 M

Milimoles of OH- ions = 34.0 * 0.200

= 6.8

As it can be seen from equation that 2 moles OH- ions are required for titration of 1 mole oxalate ions.

So milimoles of oxalic acid required = 6.8 / 2

= 3.4

Volume of oxalic acid solution = 25.0 mL

molarity of oxalic acid solution = Milimoles / volume

= 3.4 / 25

= 0.136 M

So, the concentration of an oxalic acid = 0.136 M