RP1 - Making up a standard solution and carrying out an acid-base titration

Question 1

What is a standard solution?

Answer 1

A solution of known concentration

Question 2

How do you make a standard solution?

Answer 2

1. Measure, using a balance, the mass of solid required
2. Transfer this to a volumetric flask and rinse the remaining weighing bottle content (with distilled water) into the flask so no solid is lost
3. Add a volume of distilled water to dissolve into the solid. Swirl to mix
4. Then add more distilled water up to the line on the volumetric flask. Invert multiple times to mix

Question 3

What equipment is needed to carry out a titration?

Answer 3

1. A pipette
2. Pipette filler
3. Conical flask
4. Burette

Question 4

How do you carry out a titration?

Answer 4

1. Once the pipette has been used to place one reactant into the conical flask, fill the burette with the other reactant. Record the initial volume
2. Add a few drops of indicator to the conical flask
3. Open the burette tap and allow the reactant to flow into the conical flask, swirling it to mix the contents
4. Close the burette tap once the expected colour change occurs. Use a white tile so the colour change is easily identifiable
5. Record final burette volume
6. Repeat until you get concordant results, then calculate a mean titre value

Question 5

Why are acid based indicators used?

Answer 5

1. To detect when a reaction reaches completion, usually via an observable colour change

Question 6

What are concordant results?

Answer 6

Titres that are within 0.1cm3 of each other