The pH of soil A is 7.5 while that of soil B is 4.5. Which of the two soils should be treated with powdered chalk to adjust its pH and why?

The pH of soil A is 7.5 while that of soil B is 4.5. Which of the two soils should be treated with powdered chalk to adjust its pH and why?
Answer:
Soil B having pH 4.5 should be treated with powdered chalk to adjust its pH. Soil B is too acidic. Its acidity can be reduced by adding powdered chalk (CaC03), which is a base.