Many candidates attempted this question and their performance was encouraging. In questions 4(a) and 4(b), many candidates could define liming and list the advantages
of using lime in agriculture.
However, in question 4(c), most candidates were unable to describe a simple experiment to determine the pH of a soil sample which has been previously mixed with dilute HCl. The expected answers ·include:
Description of experiment to determine pH of a soil
(i) Apparatus:
- Beakers/test tube, Red litmus paper, Blue litmus paper, soil sample, water and stirrer
(ii) Procedure:
- Put some quantity of the soil sample in the beaker and then add water to it
- Use the stirrer to mix the soil sample and water together.
- Put each of the blue and red litmus papers into the mixture inside the beaker/test tube separately.
(iii) Observation:
- The blue litmus paper will change to red
-
The red litmus paper will not change its colour
(iv) Conclusion
- The soil sample is acidic.
However in question 4(d), many candidates could list timing materials use in agriculture. 
