Q9.    Pratyush took sulphur powder on a spatula and heated it. He collected the gas
                  evolved by inverting a test tube over it, as shown in figure below.



                (a) What will be the action of gas on
                    (i) dry litmus paper?
                    (ii) moist litmus paper?

Answers (1)
D Devendra Khairwa

In the given procedure sulphur dioxide is formed.

(i) Thus gas (sulphur dioxide) has no effect on dry litmus paper.

(ii) SO2 convertes moist blue litmus paper to red due to formation of sulphurous acid. (as sulphur dioxide reacts with moisture to produce acid).