In the given situation, Dorji can test the nature of the drinks in two ways.
∙ He can taste few drops of soft drinks to find out their nature. An acidic drink is sour in taste, a basic drink is bitter in taste, and a neutral drink does not have a particular taste.
∙ He can also use litmus papers to identify the nature of the drinks. When a drop of the acidic drink is poured on a blue litmus paper, it turns red. Similarly, when a drop of the basic drink is poured on a red litmus paper it turns blue. But, when the neutral drink is poured the colour of both the litmus papers remains unchanged.