Give reason for: $\mathrm{HF}$ is a polar molecule.

Give reason for: Carbon is a tetravalent in nature.

Identify the type of overlap present in ${\mathrm{H}}_2$.

Identify the type of overlap present in ${\mathrm{F}}_2$.

Identify the type of overlap present in$\mathrm{HF}$.

In the case of bond formation in acetylene molecule: How many covalent bonds are formed?