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?
(b) Write a balanced chemical equation for the reaction taking place.

Take about 1 gram of solid NaCl in a clean and dry test tube. Add some con. H_2SO_4 and test the evolved gas with a litmus paper. Your observation is

Latha take some quantity of powder of a substance in a test tube. Heated it with spirit lamp. A gas was liberated. She sends the gas into another test tube. The colour of solution in the second test tube turned into milk white. Which substance was heated? Which gas is liberated? What was the solution taken in second test tube? Which type of chemical reactions involved the experiment?