Answers to Problems of the A Groups
447
At positive electrode:
e~ + Ni(OH) 3 ?± OH- + Ni(OH) 2
7. (a) 6.48 kcal
(d) 10.08 kcal
(b) 6.48 kcal
(e) 3.04 kcal
(c) 16.28 kcal
8. (a) AG° = -249.07 kcal; K f = 7.68 x 10
182 ; spontaneous
(b) AG° = -335.82 kcal; K, = 3.84 x 10
246
; spontaneous
(c) AG° =
16.66kcal;/C e = 5.85 x lO'
13 ; not spontaneous
(d) AG° =
25.06kcal;A: e = 3.97 x 10~
19 ; not spontaneous
9. (a) AS
0 = -43.91 cal/°C
(b) AS" = -38.60 cal/°C
10. (a) A#° = -262.16 kcal
(b) A//° = -347.32 kcal
11. (a) 4.45 x 10-'
3
(b) 1.77 x 10
83
12. +30.0cal/mole °C
CHAPTER 18
1. The oxidation numbers are
given molecule or ion.
(a) +4, -2
(b) +1, +5, -2
(c) +2, -1
(d) +3, +6, -2
(e) +2, +5, -2
(c) AS
0 = + 34.74 cal/°C
(d) AS
0 = +10.58 cal/°C
(c) A//° = +27.01 kcal
(d) A#° = +28.21 kcal
(c) 1.68 x 10
37
given for the atoms in the order in which they occur in the
(f) +1, -1
(g) +3, -2
(h) +4, -1
(0 +3, -2
(j) +6, -2
2. (a) HNO 2 + H 2 O <=s 3H
+ + NO 3 - + 2e~
(b) H 3 AsO 3 + H 2 O *± H 3 AsO 4 + 2H
+ + 2e~
(c) Al <=* A1
3+ + 3e(d) Ni <=* Ni
2+ + 2e~
(e) Hg 2
2+ ?± 2Hg
2+ + 2e(f) H 2 O 2 ?± O 2 + 2H
+ + 2e(g) 21- <±l t + 2e3. (a) 2e- + PbO 2 + 4H
+ ^ Pb
2+ + 2H 2 O
(b) e- + NO 3 - + 2H
+ ** NO 2 + H 2 O
(conc'd acid)
3e- + NO 3 - + 4H
+ ?± NO + 2H 2 O
(dilute acid)
(c) e- + Co
3+ ?± Co
2+
(d) 8e- -
(e) 2e- -
(f) e- -
(g) 2e- -
(h) 2e- -
h C1O 4 - + 8H+ ?± Cl- 4
I- BrO- + 2H
+ ** BrI- Ag
+ <=* Ag
h F 2 f± 2Fh Sn
2+ ?± Sn
- 4H 2 O
f H 2 O