Question

By giving at least two examples describe evolution of gas in a chemical reaction

Answer 1

Explanation:

Na2CO3 + HCl produces CO2

Also, Sulphuric acid with metals above hydrogen in the reactivity series replace the H2 and Hydrogen gas is released

Answer 2

The reaction in which gases are bi-products involves the evolution of gas.

• The gases are evolved as the main or bi-product in the reactions which can be collected or released in the atmosphere.
• Examples of evolved gases are oxygen, carbon dioxide, hydrogen, sulphur dioxide, hydrogen sulphide, etc.
• The common reactions are reacting the metal with an acid to evolve hydrogen gas and the reaction of sodium sulphide with hydrochloric acid.
• The chemical equations are:

$Zn+H_{2}SO_{4}$ → $ZnSO_{4}+H_{2}$

$Na_{2}S+2HCl$ → $2NaCl+H_{2}S$