Concentrated H_(2)SO_(4) is added to each of the five test tubes containing (i) NaBr, (ii) sugar, (iii) sulphur powder, (iv) KCl and (v) copper turnings. The test tubes are then heated. Identify in which of the test tubes the following changes will be observed. The observations are: evolution of a colourless gas. Support your answer with the help of a chemical equation in this case.

Concentrated H_(2)SO_(4) is added to each of the five test tubes conta

1.	Concentrated H_(2)SO_(4) is added to each of the five test tubes containing (i) NaBr, (ii) sugar, (iii) sulphur powder, (iv) KCl and (v) copper turnings. The test tubes are then heated. Identify in which of the test tubes the following changes will be observed. The observations are: evolution of a colourless gas. Support your answer with the help of a chemical equation in this case.
Answer» Solution :When conc. `H_(2)SO_(4)` reacts with KCI taken in the test tube (iv), colourless HCI gas is EVOLVED. `KCl+H_(2)SO_(4)overset(DELTA)toKHSO_(4)+Hcluarr`