Methods Of Titration

Question 1

Hazards in an experiment

Answer 1

High concentration of chemicals -> concentrations could be lowered or gloves, lab coat and googles could be worn

Question 2

Making standard solutions method

Answer 2

1. Add an amount of acid to a weighing boat making sure you record the exact weight.
2. Transfer this to a beaker adding 100cm of deionised water and stirring till completely dissolved.
3. Remove the stirring rod by rinsing it with deionised water into the beaker.
4. Place a funnel in the volumetric flask and pour in the solution, cleaning it out with deionised water into the flask.
5. Fill the rest of the flask to the graduation mark and invert several times to mix with thumb over the stopper.

Question 3

Titration method

Answer 3

1. Rinse the conical flask with deionised water and place it on a white tile.
2. Using a pipettes filler, rinse the pipettes with deionised water and then with some of the unknown solution.
3. Use the pipettes to transfer 25.0cm3 of the unknown solution to the conical flask.
4. Add about 3 drops of methyl orange indicator.
5. Rinse the burette with distilled water and the known solution.
6. Fill the burette with the known solution using a funnel and making sure the tap is filled and set it up in the stand above the conical flask.
7. Record the burette reading.
8. Add the known solution to the conical flask until the indicator changes colour adding it dropwise and swirling at the end.
9. Record the final burette reading.
10. Repeat the steps again until you get concordat results(max 0.1cm3 apart).

Question 4

Colour changes for methyl orange

Answer 4

Acid = red
Alkali = yellow

Question 5

Colour changes for Phenolphthalein

Answer 5

Acid = colourless
Alkali = pink