Define malleability.

Give reasons for the following:

Copper does not liberate hydrogen on reacting with dil.${\mathrm{H}}_2{\mathrm{SO}}_4$

Give reasons for the following:

Non-metals in general do not displace hydrogen from dilute acids.

Describe ionic compounds on the basis of the following property:

Solubility of compounds in water.

Describe ionic compounds on the basis of the following property:

Electrical conductivity.

A metal X is so soft that it can be easily cut with a knife. Its oxide, soluble in water, forms compound which turns red litmus solution blue. Identify X.

Give your answer with chemical equation.