Question

The enthalpy of neutralisation of $HCO_{3}^{-}$ (aq) with strong alkali is – 42 kJ/mole and enthalpy of neutralisation of strong acid with strong alkali is – 56 kJ/equiv. Therefore, enthalpy of dissociation of $HCO_{3}^{-}$ (aq) is-

• A. – 98 kJ/mol
• B. 98 kJ/mol
• C. 14 kJ/mol
• D. 24 kJ/mol

Answer 1

Answer: (C)

14 kJ/mol

Answer 2

$HCO_{3}^{-}$ (aq) + OH^– (aq) ¾® $CO_{3}^{2 -}$ (aq) + H₂O

DH₁ = – 42 kJ/mol.

H₂O ¾® H⁺ (aq) + OH^– (aq)

DH₂ = + 56 kJ/mol.

\ $HCO_{3}^{-}$ ¾® H⁺ + $CO_{3}^{2 -}$ DH = + 14 kJ/mol.