Investigating the Rate of Reaction Between Sodium Thiosulphate and Hydrochloric Acid

For a reaction to take place there has to be a collision with two different chemical particles. If the concentration of the hydrochloric acid was to be high the more acid particles there would be. The more acid particles there are the more likely of a collision to occur.

By adding to water to the hydrochloric acid would make the acid less concentrated, meaning there would be less acid particles and also a less likely of that a sodium thiosulphate would collide into acid particle.

Equipment :

Beakers,

Measuring cylinders

Blank piece of paper with a cross

Stop watch

Sodium Thiosulphate (Na S O)

Hydrochloric Acid (HCL)

Water (H²O).

Method :

* Collect equipment

* Draw a cross on the blank piece of paper

* Put flask on top of cross

* Pour 30cm³ of thiosulphate acid into the flask

* Add 5cm³ and start stop clock

* Stop the stop clock when the cross disappears

* Record the time

* Repeat the points above but this time use:

25 cm³ sodium thiosulphate and 5 cm³ water

20 cm³ sodium thiosulphate and 10 cm³ water

5 cm³ sodium thiosulphate and 15 cm³ water

0 cm³ sodium thiosulphate and 20 cm³ water

Results:

Sodium Thiosulphate (cm3)

Water (cm3)

Sodium Thiosulphate concentration

Hydrochloric Acid (cm3)

Exp 1, Time taken for X to disappear

Exp2, Time taken for X to disappear

Exp, Time taken for X to disappear

Average time taken for X to disappear

Reaction rate

30

0

0.15

5

43.5

44.04

45.03

44.22

0.023

25

5

0.12

5

50.95

51.29

53.59

51.94

0.019

20

0

0.9

5

70.87

78.66

79.26

76.27

0.013

5

5

0.6

5

00.48

01.44

05.35

02.32

0.005

0

20

0.3

5

80

81.08

83.50

81.82

0.005

Fair test: I made this experiment by doing the whole experiment in one day, meaning the room temperature was approximately the same. I took great care into pouring the solutions into the measuring cylinders and making sure that they were accurate, but instead of measuring cylinders I could have used a burette which would have gave me better results.

Analysis / Conclusion : The results show that, as I had predicted, the more concentrated the solution was the quicker the reaction took place. As the concentration got weaker, the reaction was slower. I also believe if you were to swoop Sodium Thiosulphate and Hydrochloric Acid for two different chemicals the same would happen.