Question

68. Step 1: H2SeO3(aq) <=> HSeO3-(aq) + H+(aq) $K_{a1}$ = 2.1 x 10-3 Step 2: HSeO3-(aq) <=> SeO32-(aq) + H+(aq) $K_{a2}$ = 5.3 x 10-9 The step-wise dissociation of selenous acid, H2SeO3(aq), is represented by the equations above. Which of the following best helps explain why the value of $K_{a2}$ is so much smaller than the value of $K_{a1}$? (A) The Se atom in H2SeO3(aq) is in a higher oxidation state than the Se atom in HSeO3(aq). (B) Water is more attracted to HSeO3-(aq) ions than to SeO32- ions, which drives the step 2 equilibrium toward the reactant. (C) The HSeO3-(aq) ions produced in step 1 are asymmetrical, but the SeO32- ions produced in step 2 are symmetrical. (D) Removing the first H+ from H2SeO3(aq) requires less energy than removing the second H+, because the second H+ is removed from a negatively charged species.

          68. Step 1: H2SeO3(aq) <=> HSeO3-(aq) + H+(aq)  $K_{a1}$ = 2.1 x 10-3
Step 2: HSeO3-(aq) <=> SeO32-(aq) + H+(aq)  $K_{a2}$ = 5.3 x 10-9
The step-wise dissociation of selenous acid, H2SeO3(aq), is represented by the equations above. Which of the
following best helps explain why the value of $K_{a2}$ is so much smaller than the value of $K_{a1}$?
(A) The Se atom in H2SeO3(aq) is in a higher oxidation state than the Se atom in HSeO3(aq).
(B) Water is more attracted to HSeO3-(aq) ions than to SeO32- ions, which drives the step 2 equilibrium toward
the reactant.
(C) The HSeO3-(aq) ions produced in step 1 are asymmetrical, but the SeO32- ions produced in step 2 are
symmetrical.
(D) Removing the first H+ from H2SeO3(aq) requires less energy than removing the second H+, because the
second H+ is removed from a negatively charged species.

68 step 1 h2seo3aq hseo3 aq haq ka1 21 x 10 3 step 2 hseo3 aq seo32 aq haq ka2 53 x 10 9 the step wise dissociation of selenous acid h2seo3aq is represented by the equations above which of 85142

Added by William H.

Question

Please give Ace some feedback