Titrations

Question 1

sulfuric acid + sodium hydroxide –> sodium sulfate + water

we have a certain volume of sodium hydroxide and we know the concentration

if we know the volume of sulfuric acid needed to neutralise the alkali, we can use this to work out the concentration of the acid

Answer 1

titrations help us to work out volume of h2so4 needed to neutralise naoh

Question 2

describe the process of titration

Answer 2

Use a pipette to transfer 25cm^3 of sodium hydroxide solution into a conical flask (the conical flask reduces the risk of splashing)

Add 5 drops of indicator such as methyl orange to the alkali in the conical flask

Place the conical flask on a white tile so we can see the colour change more clearly

Fill a burette with sulfuric acid

Add acid to the alkali until the solution is neutral. We need to add just enough for this to happen.

Once we start to see a colour change, add the acid drop by drop until the solution is neutral (for methyl orange, the colour change is from yellow to red) - where the end point has been reached

It is important to swirl the solution to make sure the acid and alkali mix.

Read the volume of acid added from the burette
When reading from the volume from the burette, ensure your eye is level with the surface of the liquid.
The surface of the liquid naturally curves - this is called the meniscus. We always read the volume of the burette at the bottom of the meniscus.

Readings should be recorded to two decimal places, ending in 0 or 5

Repeat the titration several times until you get two reading within 0.1 cm^3 (concordant results/titres). Take a mean of these for our final volume.