Question

Give Reason for the following:

a) Na and K are stored under kerosene

b) Ionic compounds in general have high melting points​

Answer 1

Answer:

a) Na and K are very reactive metals and kept in kerosene oil to prevent it from coming in contact with oxygen and moisture as they react to form their hydroxides. This is an exothermic reaction and lot of heat is generated so both the metals are kept in kerosene oil.

b) Ionic compounds have an equal number of positive and negative ions arranged in the three-dimensional lattice due to which they have high melting points. The strong force of attraction between oppositely charged ions means that ionic compounds have high melting and boiling points.

Answer 2

Answer:

a) Na and K are highly reactive metals, if exposed to air or oxygen, they will react with them, so they are stored in kerosene.

b) Ionic bonds hai have strong intermolecular force of attractions due to which it is very difficult to break the bond and melt it. So it has high melting point.