Can someone tell me if my answers are correct for the following questions? If they are not correct can you please help me!

5. Balance the following half reactions in acidic solution using the 7 step ion-electron method. Give the balanced net ionic equation.
a)Cl2 -> ClO-

Answer: Cl2 + H2O + 2e- -> 2ClO-

b)Cr3+ -> Cr2O72-

Answer: 2Cr3+ + 7H2O + 3e- -> Cr2O72- +14H+ + 12e-

c)BiO3- -> Bi3+

Answer: BiO3- + 6H+ + 5e- -> Bi3+ + 3H2O + 3e-

6.Using the 7 step ion-electron method, balance the following reaction in acidic solution.
Cu + H2SeO3 ?-> Cu2+ + Se

Answer:
oCu -> Cu2+ + 2e-
oH2SeO3 +4H+ + 4e- -> Se + 3H2O
o 2[Cu -> Cu2+ + 2e-]
H2SeO3 +4H+ + 4e- -> Se + 3H2O
oH2SeO3 +4H+ + 2Cu + 4e- -> Se + 3H2O + 2Cu2+ + 4e-
oH2SeO3 +4H+ + 2Cu -> Se + 3H2O + 2Cu2+

7.Using the 7 step ion-electron method, balance the following reaction in acidic solution.
HNO2 + MnO4- -> Mn2+ + NO3-
Answer:
oHNO2 -> NO3-
MnO4- -> Mn2+
oHNO2 + H2O-> NO3- +3H+ + 2e-
MnO4- + 8H+ + 4e- -> Mn2+ + 4H2O