Blue litmus paper is dipped in a solution. It remains blue. What is the nature of the solution? Explain.

Dorji has a few bottles of soft drink in his restaurant. But, unfortunately, these are not labeled. He has to serve the drinks on the demand of customers. One customer wants acidic drink; another wants basic and third one wants neutral drink. How will Dorji decide which drink is to be served to whom?

Explain why:

a. An antacid tablet is taken when you suffer from acidity.

b. Calamine solution is applied on the skin when an ant bites.

c. Factory waste is neutralized before disposing it into the water bodies.

Three liquids are given to you. One is hydrochloric acid; another is sodium hydroxide and third is a sugar solution. How will you identity them? You have only turmeric indicator.

Consider the following statements:

a. Both acids and bases change colour of all indicators.

b. If an indicator gives a colour change with an acid, it does not give a change with a base.

c. If an indicator changes colour with a base, it does not change colour with an acid.

d. Change of colour in an acid and a base depends on the type of the indicator.

Which of these statements are correct?

i. All four ii. a and b

iii. b and c iv. Only d