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.
$Fe _{( s )}+ H _{2} SO _{4( aq )} \longrightarrow FeSO _{4( aq )}+ H _{2( g )}$
Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in figure below.
$(a)$ What will be the action of gas on
$(i)$ dry litmus paper ?
$(ii)$ moist litmus paper ?
$(b)$ Write a balanced chemical equation for the reaction taking place.
Give reasons : Aluminium is a highly reactive metal, yet it is used to make utensils for cooking.
Give reasons : Carbonate and sulphide ores are usually converted into oxides during the process of extraction.
You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.
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 ?