Answer:
(a) HNO₂ nitrous acid 4.5 x 10^-4 is strong acid
(b) Ka expression
(c) List of Conjugate Bases
OCl⁻, S²⁻, CN⁻, NO₂⁻
(d) cyanide ion is strongest conjugate base.
(e) pH and pOH of Hypochlorous acid = 4.22 & 9.77
pH and pOH of hydrogen sulfide = 4 & 10
pH and pOH of hydrocyanic acid = 5.2 & 8.79
pH and pOH of nitrous acid = 2.17 & 11.8
Explanation:
(a) Ka and acidity are directly proportional to each other
hence nitrous acid is the strongest acid since it has highest Ka value.
(b) Ka expression of nitrous acid
HNO₂ → H⁺ + NO₂⁻
⇒
(c) Conjuagte base for HOCl hypochlorous acid = OCl⁻(hypochlorite ion)
H₂S hydrogen sulfide = S²⁻(sulphide ion)
HCN hydrocyanic acid = CN⁻(cyanide ion)
HNO₂ nitrous acid = NO₂⁻(nitrite ion)
<u>(d) We know according to Bronsted acid base concept Weak acid have strongest conjugate base</u>
according to this hydrocyanic acid is weak acid so the corresponding conjugate base i.e. cyanide ion is strongest conjugate base.
