Titrations (acids + alkalis) PAPER 2

Question 1

What does titration do?

Answer 1

• titration allows you to find out exactly how much acid is needed to neutralise a quantity of alkali (or vice versa)

Question 2

Titration experiment

Answer 2

1) using a pipette and pipette filler, add some alkali (usually 25 cm^3) to a conical flask, along with two or three drops of indicator
2) fill a burette with the acid. Make sure you do this below eye level (prevents acid from going in eyes)
3) using the burette, add the acid to the alkali a bit at a time - giving the conical flask a regular swirl. Go especially slow when you think the end point (colour change) is about to be reached
4) the indicator changes colour when all the alkali has been neutralised - e.g. phenolphthalein is pink in alkalis + colourless in acids
5) record the volume of acid used to neutralise the alkali. Repeat the process a few times to make sure you get nearly the same answer each time, making it more reliable results

Question 3

Why is a burette used?

Answer 3

Burette measure different volumes and let you add the solution drop by drop

Question 4

Titration calculation

Answer 4

mol = concentration (mol/dm^3) x volume (dm^3)