Question

Give reasons why—
(a) Hydrochloric acid cannot form an acid salt.
(b) Electronegativity increases across a period.

Hint:

Remember: Basicity refers to the number of ionizable H^+ ions in an acid. HCl is monobasic, H_2SO_4 is dibasic, and H_3PO_4 is tribasic!

Answer 1

(a) Hydrochloric acid cannot form an acid salt:
Hydrochloric acid (HCl) is a monobasic acid, meaning it has only one replaceable hydrogen ion (H⁺).
Acid salts are formed only when an acid has more than one replaceable hydrogen ion (i.e., polybasic acids) and only partial neutralization takes place.
Since HCl has only one hydrogen ion, it either gets completely neutralized or not at all, so it cannot form an acid salt.

(b) Electronegativity increases across a period:
As we move from left to right across a period, the nuclear charge increases due to an increase in the number of protons.
However, the number of electron shells remains the same, so there is no significant increase in shielding effect.
As a result, the nucleus attracts the bonding electrons more strongly, leading to an increase in electronegativity across the period.