Question

The PH of soil a is 7.5 which of the 2 soils A or B should be treated with powered chalk to adjust it PH why ?

Answer 1

acidic nature of a substance is due to the formation of H+(aq) ions in solution..
hydrogen ions are produced in the presence of water..The separation of H ions from acid like HCL molecule cannot occur in the absence of water...so, acid do not show acidic behaviour in the absence of water...

Answer 2

Acidic soil must be added to make the soil neutral.

The soil is already little basic .So it contains little OH- ions.

If acid is added the H+ions will react with OH- and water H20 is formed.

Thus acid soil is added.