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 |
Answer: 0.11
Solution
Experiments 3, 4, and 5 give consistent readings of 9.0 mL, so this is the correct titre value.
For the neutralization of oxalic acid (dibasic) with NaOH:
Number of equivalents of oxalic acid = Number of equivalents of NaOH
Solving: M
For the neutralization of oxalic acid (dibasic) with NaOH:
Number of equivalents of oxalic acid = Number of equivalents of NaOH
Solving: M
JEE Advanced · 2020 · 27 Sep 2020 · Paper 1 · Numerical answer