Identify the gas evolved in each of the following cases:-
(i) A reddish brown gas liberated on decomposition of nitric acid. (ii) Copper reacts with cold and dilute nitric acid. (iii) Dilute hydrochloric acid is added to Calcium sulphide (iv) Concentrated nitric acid is added to Sulphur.
Answers
Answer:
The decomposition of nitric acid to produce nitrogen dioxide, oxygen and water.
Copper is a reddish-brown metal. ... When copper is reacted with cold, dilute nitric acid it yields copper nitrate, water, and nitric oxide. And again it undergoes a reaction with air, which is nitric acid reacts with oxygen and gives nitrogen dioxide.
Calcium reacts with dilute hydrochloric acid to give calcium chloride and hydrogen gas. Calcium hydroxide, Ca(OH)2or slaked lime or hydrated lime, is a caustic substance produced by heating limestone at high temperature (above 825 °C) and then carefully adding water to it..
Hot and concentrated nitric acid is a powerful oxidising agent. ... So, the sulphur is oxidised from an oxidation state. Now, consider the reduction half-reaction of nitric acid decomposing to nitrogen dioxide.