A 0.10 M standard solution of hydrochloric acid (HCl) was used to find the concentration of a sodium hydroxide (NaOH) solution by titration - Leaving Cert Chemistry - Question 2 - 2007

The hydrochloric acid (HCl) solution is usually measured using the piece of equipment labelled A.

The piece of equipment used to measure the second solution is a pipette.

To properly rinse and fill the burette:

1. Rinse the burette with distilled water followed by a small amount of the hydrochloric acid solution to prevent contamination.
2. Ensure the burette is held upright and the tap is closed before filling.
3. Fill the burette above the zero mark, then open the tap to allow the liquid to drain until the bottom meniscus is on the zero mark.

Using a filter prevents contamination of the solution and ensures the liquid flows smoothly into the burette without spilling or introducing air bubbles.

One precaution is to allow the liquid to drain under gravity without touching the side of the flask to avoid liquid retention inside the burette.

A suitable indicator for this titration is methyl orange. The colour change observed at the end point was from yellow to red.

The balanced equation for the titration reaction is:

To calculate the concentration, use the formula:

Substituting the values:

Solving for $C_2$ gives:

Hence, the concentration of the sodium hydroxide solution is 0.11 M.