Acids and Bases - Science

Practical Assessment – Chemistry – Acids and Bases

Aim:

To measure the pH of several solids and liquids using universal indicator solution and a pH pen

Equipment:

Spotting tile

Universal indicator solution

Samples of several solids and liquids

pH pen

Method:

1.       Take two samples of each solid/liquid to be tested and arrange on your spotting tile. (If you are testing a solid add a drop of water and mix it before adding indicator)

2.       Place one drop of universal indicator on ONE of each sample.

3.       Use the pH pen to measure the pH of the other sample of each substance

Results:

Substance	Colour with pH	Description	pH Meter reading	Description
Eg. Substance A	Pale Blue	Weak base	8.3	Weak base
Sugar	Blue/Green	Weak base	5.8	Weak acid
Lux flakes	Blue/Green	Weak base	9.9	Average base
Detergent	Green/Yellow	Weak acid	7.8	Neutral
Toothpaste	Yellow	Weak acid	7.4	Neutral
Fruit juice	Orange	Average acid	3.6	Strong acid
Window cleaner	Blue	Average base	7.1	Neutral
Citric acid	Red/Pink	Strong acid	8.8	Weak base
Cheesels	Blue	Strong base	12.6	strong base

Conclusion:

I think that the pH readings are very very incorrect because people in my class were mixing all the chemicals, so the readings were incorrect.