Question

Observation : (1) Solution in the burette (2) Solution in the conical flask: (3) Indicator (4) End Point: Faint pink to (5) Chemical reaction : HCI + NaOH →​

Answer 1

Aim

To determine the strength of a given solution of sodium hydroxide solution by titrating it against a standard solution of oxalic acid.

Theory

This estimation involves titration of a weak acid that is oxalic acid against a strong base sodium hydroxide and phenolphthalein is the indicator of choice. The reaction between oxalic acid and sodium hydroxide is

(COOH)2 + 2NaOH -(COONa)2 + 2H2O

Since sodium hydroxide is not a primary standard a standard solution of oxalic acid is prepared and used for standardisation of sodium hydroxide.

In acid base titration at the end point the amount of acid becomes chemically equivalent to the amount of base present. In case of strong acid and strong base titration at the end point of solution the solution become neutral.

Materials Required

Burette

Pipette

Conical flask

Burette stand

Funnel

Stirrer

White glazed tile

Measuring flask

Oxalic acid (solid)

Oxalic acid (as per needed)

Sodium hydroxide solution (as per needed)

Phenolphthalein indicator (as per needed)