Question

Dorji has a few bottles of soft drink in his restaurant. But, unfortu-
nately, these are not labelled. 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?​

Answer 1

Dorji can use a litmus strip to check which drink is acidic, which is basic and which is neutral.

A red litmus strip turns to blue when dipped in basic drink.

A blue litmus strip turns red when dipped in acidic drink.

A litmus strip doesn't change when dipped in neutral drink.