Question

Explain the evolution of gas in chemical reaction . with the helps of 2 examples
Please tell fast tomorrow is my exam.​

Answer 1

Answer:

Evolution of Gas – Some chemical reactions take place with the evolution of gas. For example, when zinc reacts with hydrochloric acid, hydrogen gas is evolved with formation of zinc chloride. ... For example, barium chloride reacts with sodium sulphate and forms sodium chloride and precipitate of barium sulfate.

Answer 2

Answer:

Chemical reactions are characterised by:

1.Evolution of a gas.  

2.Change in colour.  

3.Formation of a precipitate.  

4.Change in temperature.  

5.Change in state.

Reactions showing evolution of gas:

Zn(s) + H2SO4(aq) → ZnSO4(aq )+ H2(g)

Zn(s) + 2HCl(aq) → ZnCL2(aq) + H2(g)