Give reason:
a) Ionic compounds required more energy to break down as compare to covalent compounds.
b) Solid state of an ionic compound doesn't conduct electricity.
c) Why do we need to add 0.05% carbon with iron to make bridges and railway tracks.
d) Silver articles become black when react with sulphur.
e) Brown flaky in the surface of iron rod when exposed to moisture and air.
Answers
Explanation:
a) Ionic compounds are solids and are considerably hard due to strong force of attraction between positive and negative ions . Therefore require more energy to break down this inner - ionic force of attraction.
b) Solid state of ionic compound can't conduct electricity because movement of ions is not possible in the solid.
c) Pure form of Iron is very soft and streches easily when heated. Therefore some amount of carbon ( about 0.05%) is mixed which causes the iron to become hard and strong.
d) Silver articles become black when reacts with sulphur because the reaction of silver and sulphur in air causes the formation of a layer of silver sulphide(Ag2S) which is black in colour.
As a result of this silver article becomes black.
e) we all know that when Iron comes in contact with moisture it acquires a coating of brown flasky which is called rust. This happens due to the oxidation reaction of iron. when Iron is heated it reacts with oxygen to form a mixture of iron(II) and iron(III) oxides.
Hope it helps