Titration

Question 1

How do you calculate concentration?

Answer 1

concentration = moles/ volume

volume in dm^3
conc. in mol/dm^3

Question 2

how do you perform a titration?

Answer 2

1) rinse a flask, burette and pipette with deionised water
2) use a pipette and pipette filler to measure out exactly 25 cm^3 of sodium hydroxide solution and place it into the flask
3) place the flask on a white tile
4) add three or four drops of methyl orange indicator to the flask
5) place the burette in a clamp stand then fill it with dilute hydrochloric acid
6) open the tap of the burette so that the solution fills the gap below the tap
7) record the volume of the hydrochloric acid in the burette
8) add the hydrochloric acid to the flask, steadily at the first and then more slowly near the end point.
9) when the indicator changes colour, record the volume of acid added
10) repeat the experiment

Question 3

Explain the importance of the steps taken in a titration

Answer 3

• a white tile is placed -> see colour change more clearly
• same number drops of indicator every time -> if too much could affect volume of alkali + have a much deeper colour than it should’ve had
• make sure space below tap of burette is filled with solution -> could give false result (added more acid than you had)
• swirl the flask as the dilute acid is added -> make sure that all acid + alkali has reacted
• repeat the experiment -> to calculate an accurate mean
  add the hydrochloric acid slowly at first and drop by drop near the end point -> to ensure that you get the end point