The Effect of Concentration of Hydrochloric Acid on Sodium Thiosulphate

The Effect of Concentration of Hydrochloric Acid on Sodium Thiosulphate

In this experiment I intent to investigate the effect of concentration

of hydrochloric acid on Sodium Thiosulphate. When mixed together,

these form a yellow precipitate. We are going to time the reaction

time for this experiment

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Na2 S 2 O3 + 2HCl 2 NaCl + S + H2O + SO2

Equipment Needed

To do the experiment, I will need the following equipment:

· Hydrochloric Acid

· Sodium Thiosulphate

· White Paper square with 'X' marked upon it

· A conical flask

· Measuring cylinders

· Beaker

· Water

· Stopclock

Method

1. Beaker filled with Sodium thiosulphate

2. Hydrochloric Acid bottle fetched

3. Conical flask will then be placed upon white paper with x on it.

4. For each reading throughout the final experiment, 10cm3 of acid

will be used.

5. 40cm3 of thiosulphate is to be measured in a measuring cylinder for

the purposes of the first reading and 0cm3 of water will be measured

6. The thiosulphate (and water on the other occasions) will then be

poured into the conical flask

7. Then the acid will be added, and as soon as the acid has been

added, the timer starts

8. The timer stops when the designated viewer for this test can no

longer see the 'x' beneath the flask

9. The measuring cylinders will be washed out between tests

10. The used conical flask will be replaced each time with a fresh one

11. The amount of acid will remain constant throughout the experiment

12.The amount of thiosulphate will decrease by 5cm3 after each

reading, and the amount of water will increase by 5cm3 after each

reading

(eg (1=40 thio - 0 Water) (2=35 thio - 5 Water) and so forth until 10

thio - 30 water

Safety Precautions

Due to some of the hazardous materials used in this experiment, it has

been decided that the following safety protocols be observed: