Question

(10 pts) Balance the following redox reactions by first separating the oxidation and reduction half-reactions. a. Cut (aq) + Fe (s) Fe3+ (aq) + Cu(s) b. Cu(s) + HNO3 (aq) Cu2+ (aq) + NO (g) (basic solution) c. NH(aq) + O2(g) → N03 (aq) + H2O(l) (acidic solution) d. Cd(s) + NiO(OH)(s) + Ca(OH)2(s) + Ni(OH)2(s) (Nicad battery) e. The oxidation of iodide ion (1) by permanganate ion (MnO4) in basic solution to yield molecular iodine (12) and manganese(IV) oxide (MnO2).

Answer 1

1) Cu+ + Fe ------> Fe3+ + Cu

Divide equations into two half-reactions:

Fe ----> Fe3+ + 3e- Cu+ + 1e- --------> Cu

Multiply by an inetger to balance number of electrons:

Fe ----> Fe3+ + 3e- 3Cu+ + 3e- --------> 3Cu

Add reactions and cancel like species:

Fe + 3Cu+ + 3e- --------> Fe3+ + 3e- + 3Cu

Fe + 3Cu+ -------> Fe3+ + 3Cu

at 2) Cupt HNO (a) Cu2tag) + NO(g) basic solution - Eu ting Cut +No - Oxidation Cu - Cat Reduction #ño No Balance the atoms except Hand o Cu Cult HING NO - Balance H and o atoms Cu Cu at HNQ+ 3 H - NO+2H₂O - As reaction is taking place in basic medium, add anoH. ion to each side for every tion. -Ba Cu Cu c at NO₃ + 3 Hot - Balance charge: Cupcu? 7 2 3 Ng7 to +36 NO +240 +300 No +240 + 304 e muitine teciente by integers producing lowest common multiple ou y yoo poodidy X3 x2 HNO + 3 H₂O+3é Nota+60+304 3 cu 3 curt the QHNG + 6 Hortê 2NO+ 4H0+ 604 Add half reactions 3 Cut at Ng + 6H₂O+bé 3 cuat +6é + 2NO+440+ 604 - 3.cu taHNO + 2H2O 3 Cu2+ + 2NO+604 + Cu cat the 5 -2 + - 3 Cugt 2HNO+244014) 3 Cutest ano at 601 3 Nhut (aq) +0(8) NO₂ (aq) + H₂O(0) acidic solution - th & North - oxidation; Ñ HA NO Reduction: & ho - Balance the atoms except H and o WHAT NO; Q atho - Balance Hand o atoms +1 -2

x1 NH4+ + 340 NO3 +1ort Oat 4H+ 2H₂O - Balance the charge - NH4 + 3HO NO +104t +8e O2 + 4H+ the ato - Multiply coefficients of all species by integers producing lowest common multiple NH4+370 NO3 + 104 +8ê x2 O + 4H+ +hé > 2H2O NHAT + 340 NO+ 10H + sé 20 + 8 H+ +8 e 4H₂O - Add half-reactions NH4+20 + 3H₂Ot 84 +8é NO₂ + 4H₂O + lort+8ē - NH₃ + + 20 NO3 + totalt +2 -2 + NH4+ (aq) +20 (9) NOz aq) + Ho (e) + 2H 4) Cd(s) + NIO (OH)S) > cd (OH)2 ($) + N' OH)2(S) - că + Root Edcorn + Micore - cd ca Cot Nicolor Nicola - Balance the atoms except Hando Cd Cd (OH)2 Nio (OH) Ni(OH)2 & Balance H and o Cd +240 CdCOH)2 taht NiocoH NiCOH)₂ Balance of ions Cd + 2H₂O + 2010 CLCOH) tato NiOOH + tho NiCOH + OH - Balance the charge (dotato + 204 Cacord+athotae Nto(он) + H, 0+ e - L(он) + OH - Multiply the coefficients of all species I producing the lowest common multiple Cd + 2H2O + 2017 Cd (OH)2+ 2H₂Otał x1 NiocoH) thote NiCOH)₂ + 204 x2

Cd +2tot 2015 Cdor +240 + 20 2 Nioco +240 +2e Ni(OH)₂ + 204 Add the half-reactions Cd + 2 Nio (OH) + 440 +2014+2€ (door) +2 NECOH + 2+60+204 the - Cdt a Nio(OH) +240 C&COH)2 + 2 NiCOH -- Cd(s) + 2NiO(OH) (9) + 2H20 - > cd (OH)2+2 Ni(01),