Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the chemical reaction when iron reacts with dilute $H_2SO_4$.
Hydrogen gas is evolved when dilute hydrochloric acid is added to a reactive metal.
When iron reacts with dilute $H _{2} SO _{4}$ iron $(II)$ sulphate with the evolution of hydrogen gas is formed.
$Fe _{( s )}+ H _{2} SO _{4( aq )} \longrightarrow FeSO _{4( aq )}+ H _{2( g )}$
What are amphoteric oxides? Give two examples of amphoteric oxides.
Metallic oxides of zinc, magnesium and copper were heated with the following metals.
Metal | Zinc | Magnesium | Copper |
Zinc oxide | - | - | - |
Magnesium oxide | - | - | - |
Copper oxide | - | - | - |
In which cases will you find displacement reactions taking place ?
Give an example of a metal which
$(i)$ is a liquid at room temperature.
$(ii)$ can be easily cut with a knife.
$(iii)$ is the best conductor of heat.
$(iv)$ is a poor conduct of heat.
What type of oxides are formed when non-metals combine with oxygen?
A man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?