2. 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 solution measured using the piece of equipment A is the sodium hydroxide (NaOH) solution.

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

To properly rinse and fill the pipette (A), first rinse it with deionised water. Next, rinse it with the solution it will measure, filling it part way and then expelling it, ensuring that the solution coats the inside of the pipette. Finally, fill the pipette above the line, keeping the liquid's meniscus resting on the line for an accurate measurement.

It is preferable to use a filler rather than your mouth because the caustic solution (NaOH) can be harmful if swallowed and may cause the risk of infection transfer.

One precaution to take when transferring the liquid is to allow the pipette to drain freely under gravity, ensuring that no drop remains at the tip of the pipette.

A suitable indicator for this titration is methyl orange. The colour change observed in the titration flask at the end point is from yellow to red (or pink).

The balanced equation for the titration reaction is:

Using the formula for concentration, we can calculate the concentration of the sodium hydroxide solution as follows:

ext{Concentration} = rac{27.5 imes 0.10}{25.0} = 0.11 ext{ M}