3. Give reason why:
2. A piece of calcium metal when dropped in water, the gas evolved do not catch fire
b). Metals when react with nitric acid do not produce Hą gas.
Answers
Answer:
a) The hydrogen gas evolved does not support combustion and so it does not catch fire.
b) The hydrogen gas evolved is oxidized to water and so, H2 gas is not formed.
Explanation:
When metals react with water, a metal hydroxide is formed and hydrogen gas is evolved.
When metals react with acid, a salt of the metal and the acid is formed and hydrogen gas is evolved.
In both cases, hydrogen gas is evolved and hydrogen gas does not support combustion.
However, when metals react with Nitric acid, hydrogen gas is not formed since Nitric acid is a strong oxidizing agent.
Instead of forming hydrogen, it oxidizes the hydrogen to water and itself it is reduced to any of the oxides.
The answers:
a) The hydrogen gas evolved does not support combustion and so it does not catch fire.
b) The hydrogen gas evolved is oxidized to water and so, H2 gas is not formed.
A piece of calcium metal when dropped in water, the gas evolved do not catch fire
b). Metals when react with nitric acid do not produce Hą gas.
Explanation:
A piece of calcium metal when dropped in water, the gas evolved do not catch fire
When a calcium metal is dropped in water it forms calcium hydroxide and hydrogen gas so liberated is non supporter of combustion .
Ca + H₂O ----> Ca(OH)₂ + H₂
Metals when react with nitric acid do not produce H₂ gas.
When any metal reacts with nitric acid , it does not produces hydrogen gas because Nitric acid is a powerful oxidising agent , it oxidises hydrogen to water and along with it metal nitrate is formed .
M + HNO₃---> metal nitrate + Water