Question

in a very polluted city, water from the first rain in monsoon season is collected in a beaker. Which
of the following changes will it have on a litmus paper?
(A) Turn red litmus blue
(B) Tur blue litmus red
(C) Both (A) and (B)
(D) It will have no effect on litmus paper
05. OPTIONS:​

Answer 1

Answer:

This is an activity-based question in which you are supposed to collect rainwater from different places and compare their results on the basis of following parameters :

a) pH of the water

b)The action of water on blue litmus paper

c)The action of water on red litmus paper

d)Effect of an indicator like phenolphthalein and methyl orange

Conclusion :

If we take samples of rainwater from different places, we observe the following results :

the pH of water is in between 1-6

Blue litmus paper turns red

No change in the colour of red litmus paper

No change in the colour of rainwater on adding phenolphthalein

rainwater turns red in color on adding methyl orange.

The above observations show that rainwater is acidic in nature. For further assurance, we can compare blue litmus paper dipped in different samples of rainwater with a pH scale.

If rainwater is acidic, then its pH must be in the range of 0-6.

The strength of ac acid depends on its pH value i.e. lower the value of pH, higher will be the strength of an acid and vice-versa.