Question

Which statement correctly relates two substances from this reaction?

Answer 1

We have to know which two substances are related correctly.

The correct answer is: (C) H₃O⁺ is the conjugate acid of H₂O.

In an acid-base reaction, an acid reacts with a base and gives a conjugate base and conjugate acid. The reaction is shown below:

Acid₁ + Base₂ ⇄ Conjugate Base₁ + Conjugate Acid₂

In the reaction H₂CO₃ + H₂O ⇌ H₃O⁺ + HCO₃⁻, H₂CO₃  is an acid because it releases H⁺ ion and converts to HCO₃⁻. Here HCO₃⁻ is the conjugate base of H₂CO₃ ( according Arrhenius theory).

H₂O accepts H⁺ ion and is converted to H₃O⁺ , thus H₂O behaves as Bronsted base. So, H₃O⁺ is the conjugate acid of Bronsted base H₂O.

Hence, the correct answer is: (C) H₃O⁺ is the conjugate acid of H₂O.