Give a reason for each of the following:

(i) Ionic compounds have a high melting point.

(ii) Inert gases do not form ions.

(iii) Ionisation potential increases across a period, from left to right.

(iv) Alkali metals are good reducing agents.

(v) Conductivity of dilute hydrochloric acid is greater than that of acetic acid.

(i) Ionic compounds have ionic bonds so there exists a strong force of attraction between the oppositely charged ions, so a large amount of energy is required to break the strong bonding between the ions. Hence, ionic compounds have a high melting point.

(ii) Inert gases have completely filled octet which makes them extremely stable. They neither lose, nor gain electrons. Hence, they do not form ions.

(iii) The ionisation potential of an element increases across a period because the atomic size decreases due to an increase in nuclear charge and electrons in the outermost shell are more strongly held because of which greater energy is required to remove the electron.

(iv) Alkali metals have one electron in the outermost shell and hence during reactions they readily give the valence electron and get themselves oxidised. Hence, they are good reducing agents.

(v) Dil. H₂SO₄ is a strong electrolyte and acetic acid is a weak electrolyte. Therefore, dil. H₂SO₄ allows large amount of electricity to flow through it and is a good conductor of electricity whereas acetic acid allows small amount of electricity to flow through it and is a poor conductor of electricity. Hence, electrical conductivity of dilute hydrochloric acid is greater than that of acetic acid.