1. S2/3 Chemistry
Titrations

2. Learning Intentions
We are learning how to carry out an accurate acid/base neutralisation reaction, using a titration technique.
We are learning how to complete a volumetric titration calculation, which will allow unknown concentration of either an acid or an alkali to be calculated.

3. Success Criteria I can carry out an acid/base titration accurately.
I can accurately dilute an acid/alkali.
I can complete a volumetric titration calculation.

4. Titration
When an acid and alkali react together, a salt and water are formed.

5. Titration
When an acid and alkali react together, a salt and water are formed.
It is possible to find out exactly how much alkali is needed to neutralise an acid by carrying out a titration.

6. Titration Equipment
burette

7. Titration Equipment
burette
pipette

8. Titration Equipment
burette
pipette
alkali
acid

9. Titration Equipment
burette
Conical
flask
pipette
alkali
acid

10. Titration Equipment

11. Titration Method
The pipette is used to accurately measure 25ml of alkali

12. Titration Method
The pipette is used to accurately measure 25ml of alkali
The alkali is placed in the conical flask and five drops of indicator are added.

13. Titration Method
The pipette is used to accurately measure 25ml of 0.1 mol/l alkali
The alkali is placed in the conical flask and five drops of indicator are added.
Acid is added to the conical flask carefully using the burette

14. Titration Method
The pipette is used to accurately measure 25ml of alkali
The alkali is placed in the conical flask and five drops of indicator are added.
Acid is added to the conical flask carefully using the burette
The end point is reached when the indicator changes colour

15. Titration Calculation
start
end
Total (ml)
rough
8.9
1st
8.4
2nd
8.2
The rough calculation is always discarded and an average
Taken of the two remaining results.

16. Titration Calculation
start
end
Total (ml)
rough
8.9
1st
8.4
2nd
8.2
The rough calculation is always discarded and an average
Taken of the two remaining results.
Average acid volume 8.3ml

17. Titration Calculation
Titration calculations always start with a balanced equation

18. Titration Calculation
Titration calculations always start with a balanced equation
HCl + NaOH NaCl + H2O

19. Titration Calculation
Titration calculations always start with a balanced equation
HCl + NaOH NaCl + H2O
1 mol
1 mol
1 mol
1 mol

20. Titration Calculation
Calculate the moles of alkali added
N = c x v
Number of moles n c v
Volume in litres
Concentration in mol/i

21. Titration Calculation
Calculate the moles of alkali added
n = c x v
n = conc of alkali x volume in litres
n = 0.1 x 0.25
N = moles

22. Titration Calculation
At the end point of the titration the number of moles of acid must equal the number of moles of alkali

23. Titration Calculation
Moles of alkali = mole

24. Titration Calculation
Moles of alkali = mole
Moles of acid = moles

25. Titration Calculation
Calculate the concentration of the acid
Number of moles n c v
Volume in litres
Concentration in mol/i

26. Titration Calculation
Calculate the concentration of the acid
c = n = = 0.12mol/l v

27. Titration Calculation
acid alkali PVC = PVC
Power of acid
Concentration of acid
Volume of acid