Answer:
(a) HNO₂ nitrous acid 4.5 x 10^-4 is strong acid
(b) Ka expression [tex]Ka = \frac{[H^{+}][NO_{2} ^{-}] }{[HNO_{2}] }[/tex]
(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⁻
⇒ [tex]Ka = \frac{[H^{+}][NO_{2} ^{-}] }{[HNO_{2}] }[/tex]
(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)
(d) We know according to Bronsted acid base concept Weak acid have strongest conjugate base
according to this hydrocyanic acid is weak acid so the corresponding conjugate base i.e. cyanide ion is strongest conjugate base.
