Mention the reasons for the following:
1. Covalent compounds are non-conductors of electricity
2. Covalent compounds are insoluble in water
3. Ionic compounds are hard & brittle
4. Ionic compounds are good conductor of electricity in molten state
Answers
1. The covalent compounds are formed due to the sharing of electrons .
When all the electrons in the compound are shared in bonds , there are no free electrons available to conduct electricity.
Thus covalent compounds are non conductors of electricity.
2. Covalent compounds are non-polar in nature and water is polar in nature . Due to the non-polar nature of covalent compounds they don't dissolve in water .
3. The ionic compounds are hard and brittle because the anions and cations are tightly packed due to strong forces of attraction.
4. Ionic compounds conduct electricity in molten state because the ions in the molten state are free and can conduct electricity.
Reasons for the statements is as follows-
1. Covalent compounds are non-conductors of electricity
Covalent compounds are formed by sharing of electrons.
This leaves them with no free electron to conduct electricity, thus they are non conductors of electricity.
2. Covalent compounds are insoluble in water
Covalent bonds are formed by non polar compounds.
Water is a polar solvent.
Thus, compounds dissolve in water when polar compounds interact with polar hydrogen and oxygen molecule. Hence, they do not dissolve in water.
3. Ionic compounds are hard & brittle
Ionic compounds are hard due to strong ionic interaction between positively and negatively charged ions. The brittleness of ionic compounds occur due to presence of non directional bonds between them.
Brittle refers to materials which are hard but can break easily.
4. Ionic compounds are good conductor of electricity in molten state
In molten state, ionic compounds are present in the form of ions.
The ions present are cations and anions.
This results in presence of free electrons which help conduct electricity.