5.00 mL of 0.10 M oxalic acid solution taken in a conical flask is titrated against NaOH from a burette using phenolphthalein indicator. The volume of NaOH required for the appearance of permanent faint pink color is tabulated below for five experiments. What is the concentration, in molarity, of the NaOH solution? Exp. No. Vol. of NaOH(mL) 1 12.5 2 10.5 3 9.0 4 9.0 5 9.0

Question

5.00 mL of 0.10 M oxalic acid solution taken in a conical flask is titrated against NaOH from a burette using phenolphthalein indicator. The volume of NaOH required for the appearance of permanent faint pink color is tabulated below for five experiments. What is the concentration, in molarity, of the NaOH solution? Exp. No. Vol. of NaOH(mL) 1 12.5 2 10.5 3 9.0 4 9.0 5 9.0 (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

No. of eq. of oxalic acid = No. of eq. of NaOH or (5.00 × 0.10/1000) × 2=(9.0 × M/1000) × 1 ∴ Molarity of NaOH solution =(1/9) =0.11 M

No. of eq. of oxalic acid = No. of eq. of NaOH or 10005.00×0.10​×2=10009.0×M​×1 ∴ Molarity of NaOH solution =91​ =0.11M

No. of eq. of oxalic acid $=$ No. of eq. of $N a O H$
or $\frac{5.00 \times 0.10}{1000} \times 2 = \frac{9.0 \times M}{1000} \times 1$
$∴$ Molarity of $N a O H$ solution $= \frac{1}{9}$
$= 0.11 M$