Pracitcal 3 - Standardisation of an acid solution

Question 1

What’s the aim of this practical?

Answer 1

To find the concentration of HCL using a standard solution of anhydrous sodium carbonate

Question 2

What type of sodium carbonate is used in this practical?

Answer 2

Anhydrous

Question 3

Sodium carbonate symbol

Answer 3

Na2CO3

Question 4

What’s the risk associated with Na2CO3?

Answer 4

Irritant

Question 5

How much anhydrous Na2CO3 do we use in this practical?

Answer 5

2.75+-0.1g

Question 6

What’s the concentration of the acid used?

Answer 6

0.2moldm^3

Question 7

What’s the risk of the acid?

Answer 7

Irritant

Question 8

Which acid is used?

Answer 8

HCl

Question 9

How much indicator do we add?

Answer 9

3 drops

Question 10

What type of indicator is used?

Answer 10

Methyl orange indicator

Question 11

What colour does methyl orange change from and to during a titration?

Answer 11

From yellow to pink/red

Question 12

Equation to learn from sodium carbonate reacting with hydrochloric acid

Answer 12

Na2CO3 + 2HCl —> 2NaCl + CO2 + H2O

Question 13

How do we find out the concentration of the acid at the end?

Answer 13

1. Moles in NaCO3 (m divided by M)
2. Moles in HCl (molar ratio)
3. Concentration of HCl (n divided by V pipetted - remember to transfer to dm^3)