Colourless compound X obtained from sea water used in daily meals is taken in a test tube. Concentrated $H_{2}S{O}_4$ was added to the test tube. A pungent smelling gas Y comes out which does not affect dry blue litmus paper but turns moist blue litmus paper red. Identify X and Y. Write the chemical reactions involved.

Q. A student prepared hydrogen chloride gas by treating sodium chloride with concentrated sulphuric acid in a test-tube. He held a strip of dry blue litmus paper in HCl gas coming out of the test-tube. The student observed that on coming in contact with HCl gas, the colour of blue litmus paper :
(1) turned yellow
(2) turned violet
(3) remained blue
(4) turned red

Q.

Ammonia is a brown coloured, pungent-smelling gas which turns moist blue litmus paper into the red colour.

Q. Reactin of NaCI with conc. $H_{2}S{O}_4$ liberates a gas X that turns moist blue litmus paper red. When gas X is passed into a test tube containing egg shell powder suspended in water another gas; Y is generated which when passed through time water makes it milky. The gases X and Y respectively, are

Q. An element 'X' is yellow coloured solid, insoluble in water but soluble in carbon disulphide. It has a low melting point ${114.5}^{o}C$. It boils at ${445}^{o}C$ and it burns with pale blue flame forming pungent smelling gas 'Y' which turns moist blue litmus red and finally colourless. 'X' and 'Y' are: