Concentration of acids in titrations

Question 1

Suppose 25ml aliquot of HCl reqiures 11.7ml of 0.15mol/L calcium hydroxide to be neutralised. Calculate the concentration of HCl.

Answer 1

1. Chemical equation
2. Molar ratio of the two substances
3. Conc =moles/volume

Question 2

What is the rinsing procedure of the pipette during the reaction?

Answer 2

Pipette is used to carry the 25mL aliquot of diluted critic acid. The pipette must initially be rinsed with demineralised water three times to remove impurities present. The pipette must then be rinsed with the diluted solution 3 times to ensure the pipette transfers precise amount of moles, and is not diluted by the residue of the water.

Question 3

Calculate the concentration of critic acid in solution, given a tables of titres.

Answer 3

1. Find the average volume used, based on concordant titres.
2. Molar ratio
3. c=moles//volume

Question 4

With Melanie accidentally washed the conical flask with a titrant. Explain what effect would it have on final conc

Answer 4

Some of the acid added is immediately neutralised when washing the conical flask last with the titrant. This results in the concentration of acetic acid measured being lower than true concentration.