When equal molar amounts of these sets of compounds are mixed m aqueous solution
ID: 999393 • Letter: W
Question
When equal molar amounts of these sets of compounds are mixed m aqueous solution, which will form a buffer? HCl with Nacl HCl with NaOH NaOH with Na_2CO_3 NH_3 with NH_4Cl The pH of a 0.0100 M solution of a weak acid. HA. Is 3.76. What is the percent ionization of HA for this solution? 0.077% 0.58% 1.7% 5.8% Which is the most prevalent species in a 025 M aqueous solution of phosphoric acid. H_3PO_4? H_3PO_4 H -2PO^-_4 HPO^3-_4 H_3O^+ Which titration has an equivalence point with a basic pH? titrating NH_3/aq) with HCl(aq) titrating HNO_3(aq) with KOH(aq) titrating HNO_2(aq) with KOH(aq) titrating HCl_4/aq) with Ca(OH)_2(aq) Which figure best represents a concentrated aqueous solution of Hl? (Water molecules are not shown) A current of 0.150 A is passed through an aqueousCuSO_4 solution for 10.0 minutes. What mass of Cu is plated out? (Assume 100% yield.) 0.000494 g 0.0592 g 0.0296 g 0.0148 g The oxidation number of carbon changes from in this redox reaction: 2MnO_4^- (aq) + 3C_2O_4^2- (aq) + 4OH^- (aq) implies 2MnO_2(s) + 6CO_3^2 (aq) + 2H_2O(l) +6 to +4 +4 to +3 +3 to +4 +3 to +6 Which species is the most powerful reducing agent at standard conditions? Na^+ (aq) + e^- implies Na(s) E degree = -2.71 V Fe^2+ (aq) + 2e^- implies Fe(s) E degree = -0.45 V O_2(g) + 2H_2O(l) + 4e^- implies 4OH^- (aq) E degree = 0.40 V I_2(s) + 2e^- implies 2l^- (aq) E degree = 0.54 V Na(s) Fe^2+ (aq) OH^- (aq) I_2(s) For this galvanic cell reaction 3HNO_2 (aq) + BrO_3^- (aq) implies 3H^+ (aq) 3NO_3^- (aq) + Br^- (aq) the Nernst equation implies that the galvanic cell will have a more negative voltage if you: Increase the pH. Decrease the Br^- concentration. increase the BrO_3^- concentration. increase the NO_3^- concentration. The reaction Zn(s) + Ni^2+ (aq) implies Zn^2+ (aq) + Ni(s) occurs in the galvanic cell shown. Which statement is true? Electrons flow to the Zn electrode. Na^+ ions flow toward the Ni electrode. Electrons flow to the Zn electrode. Na^+ ions flow toward the Zn electrode. Electrons flow to the Ni electrode. Na^+ ions flow toward the Ni electrode. Electrons flow to the Ni electrode. Na^+ ions flow toward the Zn electrode.Explanation / Answer
13) D
Buffer = weak base and its salt formed from strong acid.
Therefore,
NH3 and NH4Cl acts as buffer. ( NH3 is a weak base)
14) We know that
[H+] = 10-pH = 10-3.76 = 1.7 x10-4 M
We know that [H+] = Ca , a = percent ionization
a = [H+]/C
= 1.7 x10-4 M / 0.01 M
= 1.74 x 10-2
= 1.7 %
Therefore,
percent ionization of HA = 1.7 %
16) C
Tittation of weak acid HNO2 with strong base KOH has basic pH.
20) More negative Eo value, stronger the reducing agent.
Therefore,
Na is the powerful reducing agent.