In an aqueous solution, the ionization constants for carbonic acid are

${K}_{1} = \text{4.2} \times 1 {0}^{- 7}$ and ${ K}_{2} = \text{4.8} \times 1 {0}^{- 11}$

Select the correct statement for a saturated $\text{0.034 M}$ solution of the carbonic acid:

Question

In an aqueous solution, the ionization constants for carbonic acid are

{K}_{1} = \text{4.2} \times 1 {0}^{- 7}

and

{ K}_{2} = \text{4.8} \times 1 {0}^{- 11}

Select the correct statement for a saturated

\text{0.034 M}

solution of the carbonic acid:

Quantrex Academy · Accepted Answer

Correct answer: D. The concentration of H^ + and HCO _ 3 ^ - are approximately equal.

cases H _ 2 CO _ 3 & ⇌ & H^ + & + & HCO _ 3 ^ - ; & K _ 1 & = & 4.2 × 1 0 ^ - 7 HCO _ 3 ^ - & ⇌ & H^ + & + & CO _ 3 ^ 2 - ; & K _ 2 & = & 4.8 × 1 0 ^ - 1 1 cases ∵ K _ 1 ≫ K _ 2 , so H _ 2 CO _ 3 ionises more than HCO _ 3 ^ - and hence, contribution of H^ + is mostly due to ionization of carbonic acid. Thus, the concentrations of H^ + and HCO _ 3 ^ - are approximately equal.

In an aqueous solution, the ionization constants for carbonic acid...

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