In aqueous solution,the ionization constants | vedclass

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(C) For the first dissociation step: $H_2CO_3(aq) ightleftharpoons HCO_3^-(aq) + H^+(aq)$.Given $K_1 = 4.2 	imes 10^{-7}$ and initial concentration

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The concentrations of $H^{+}$ and $HCO_3^-$ are approximately equal.

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(C) For the first dissociation step: $H_2CO_3(aq) ightleftharpoons HCO_3^-(aq) + H^+(aq)$.Given $K_1 = 4.2 	imes 10^{-7}$ and initial concentration $C = 0.034 \ M$.Since $K_1$ is very small,$[H^+] \approx [HCO_3^-] = \sqrt{K_1 	imes C} = \sqrt{4.2 	imes 10^{-7} 	imes 0.034} \approx 1.195 	imes 10^{-4} \ M$.For the second dissociation step: $HCO_3^-(aq) ightleftharpoons CO_3^{2-}(aq) + H^+(aq)$.$K_2 = \frac{[CO_3^{2-}][H^+]}{[HCO_3^-]}$.Since $[H^+] \approx [HCO_3^-]$,we have $[CO_3^{2-}] = K_2 = 4.8 	imes 10^{-11} \ M$.Comparing the values,$[H^+] = [HCO_3^-] = 1.195 	imes 10^{-4} \ M$,which are approximately equal.

In aqueous solution,the ionization constants for carbonic acid are $K_1 = 4.2 \times 10^{-7}$ and $K_2 = 4.8 \times 10^{-11}$. Select the correct statement for a saturated $0.034 \ M$ solution of carbonic acid.

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