Competitive Exams: Chemistry MCQs (Practice-Test 11 of 31)

  1. Consider the following standard reduction potentials, half reactionEo, V Fe3 + (aq) + e- ⇔ Fe2 + (aq) 0.77 H2O2 (aq) + 2e- ⇔ 2OH- (aq) 0.88

  2. For the voltaic cell reaction below, calculate the Fe2 + concentration (in M) that would be needed to produce a cell potential equal to 0.16 V at 25oC when (OH-) = 0.10 M (Fe3 + ), = 0.50 M and (H2O2) = 0.35 M.

  3. 2Fe2 + (aq) + H2O2 (aq) → 2Fe3 + (aq) + 2OH- (aq)

  4. Consider the following standard reduction potentials, half reactionEo, V Ni2 + (aq) + 2e- ⇔ Ni (s) -0.23 Co2 + (aq) + 2e- ⇔ Co (s) -0.28 Fe2 + (aq) + 2e- ⇔ Fe (s) -0.41 Cr3 + (aq) + 3e- ⇔ Cr (s) -0.74 Mn2 + (aq) + 2e- ⇔ Mn (s) -1.03

  5. which of the following metals could be used successfully to galvanize steel?

    1. Ni only

    2. Ni and Co

    3. Fe only

    4. Mn only

    5. Mn and Cr

  6. Consider the following standard reduction potentials, half reactionEo, V Ag + (aq) + e- ⇔ Ag (s) 0.800 AgI (s) + e- ⇔ Ag (s) + I- (aq) -0.164

  7. Calculate the value of the solubility product equilibrium constant, Ksp, at 25oC for silver iodide (AgI).

  8. AgI (s) ⇔ Ag + (aq) + I- (aq)

  9. Which of the following is TRUE for an operating voltaic cell?

    1. G > 0; E = 0

    2. G < 0; E < 0

    3. G = 0; E > 0

    4. G = 0; E = 0

    5. G < 0; E > 0

  10. Consider the following standard reduction potentials, half reaction Eo, V, Cu2 + (aq) + 2e- ⇔ Cu (s) 0.34, MnO4- (aq) + 2H2O (l) + 3e- ⇔ MnO2 (s) + 4OH- (aq) 0.59 O2 (g) + 2H3O + (aq) + 2e- ⇔ H2O2 (aq) + 2H2O (l) 0.68 and the following redox reactions, H2O2 (aq) + 2H2O (l) + Cu2 + (aq) ⇔ O2< (g) + 2H3O + (aq) + Cu (s), 2MnO4- (aq) + 4H2O (l) + 3Cu (s) ⇔ 3Cu2 + (aq) + 2MnO2 (s) + 8OH- (aq), 2MnO4- (aq) + 10H2O (l) + 3H2O2 (aq) ⇔ 3O2 (g) + 6H3O + (aq) + 2MnO2 (s) + 8OH- (aq), Which of the redox reactions above will be spontaneous under standard conditions?

    1. i only

    2. ii only

    3. i and iii

    4. ii and iii

    5. None of these.