What is the hydroxide-ion concentration in a 0.16 M solution of Na₂CO₃? For carbonic acid,Ka₁ = 4.2 × 10^-7 and Ka₂ = 4.8 × 10^-11.(K_w = 1.0 × 10^-14) A)5.8 × 10^-3 M B)2.0 × 10^-4 M C)6.2 × 10^-5 M D)4.5 × 10^-9 M E)2.8 × 10^-6 M

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Quizplus · Accepted Answer

NaHCO3 is a salt of a weak acid (H2CO3) and a strong base (NaOH). When it dissolves in water, it hydrolyzes to form HCO3- and Na+. The HCO3- can further lose a proton to form CO3^2- and H+, which decreases the H+ concentration, increasing the pH and thus the OH- concentration. Given the pKa values, the solution is basic. To find the OH- concentration, we use the Kw = [H+][OH-]. Since we don't have direct values for [OH-] and the solution's basic nature, we infer that the OH- concentration must be significant but not extremely high, making choice A the most plausible without detailed calculations.

What Is the Hydroxide-Ion Concentration in a 0