how would the use of acid help identify a chalky soil?

Answer 1

Chalk is calcium carbonate (CaCO3) and most commonly you would use hydrochloric acid (HCl) to identify it. When in contact with one another you get the products of calcium chloride (CaCl2), water (H2O), and carbon dioxide (CO2). Fizzing will occur because of the carbon dioxide thus indicating the presence of chalk in the soil.

Answer 2

you would see a chemical reaction, like foaming or fizzing with a little smoke.