Questions: Which species is the conjugate acid of HCO3^-? A) CO3^2- B) H2CO3 C) H2O D) CO2

Transcript text: Which species is the conjugate acid of $\mathrm{HCO}_{3}{ }^{-}$? A) $\mathrm{CO}_{3}{ }^{2-}$ B) $\mathrm{H}_{2} \mathrm{CO}_{3}$ C) $\mathrm{H}_{2} \mathrm{O}$ D) $\mathrm{CO}_{2}$

Solution

Solution Steps

Step 1: Understanding Conjugate Acids and Bases

A conjugate acid is formed when a base gains a proton ($ \text{H}^+ $). In this context, we need to identify which species is formed when the bicarbonate ion ($\mathrm{HCO}_{3}^{-}$) gains a proton.

Step 2: Analyzing the Options

Option A: $\mathrm{CO}_{3}^{2-}$ - This is the carbonate ion, which is formed when $\mathrm{HCO}_{3}^{-}$ loses a proton, not gains one. Therefore, it is not the conjugate acid.
Option B: $\mathrm{H}_{2}\mathrm{CO}_{3}$ - This is carbonic acid, which is formed when $\mathrm{HCO}_{3}^{-}$ gains a proton. Thus, it is the conjugate acid of $\mathrm{HCO}_{3}^{-}$.
Option C: $\mathrm{H}_{2}\mathrm{O}$ - Water is not related to the protonation of $\mathrm{HCO}_{3}^{-}$ in this context.
Option D: $\mathrm{CO}_{2}$ - Carbon dioxide is not formed by the addition of a proton to $\mathrm{HCO}_{3}^{-}$.