(a) Covalent compounds exits as gases, liquids of soft solids because they have weak forces of attraction between their molecules.
(b) Pure covalent bond exists between two elements which have similar electronegative attracts the shared pair pf electrons towards itself. As a result, hydrogen acquires partial negative charge. SO, hydrogen chloride can be termed as polar covalent compound.
\(\overset{\delta^+}{H}-\overset{\delta^+}{C}\)
