Question

Part A Complete and balance the following equation:

NO?2(aq)+Cr2O2?7(aq)?Cr3+(aq)+NO?3(aq) (acidic solution)

Express your answer as a chemical equation. Identify all of the phases in your answer.

Identify the oxidizing and reducing agents in equation above.

Express your answers as chemical expressions separated by a comma

Part C

Complete and balance the following equation:
BrO?3(aq)+N2H4(aq)?Br2(l)+N2(g) (acidic solution)

Express your answer as a chemical equation. Identify all of the phases in your answer.

Part D

Identify the oxidizing and reducing agents in equation above.

Express your answers as chemical expressions separated by a comma.

Answer 1

Part A)

NO2-(aq) --> NO3-(aq)

NO2-(aq) + H2O(l) --> NO3-(aq)

NO2-(aq) + H2O(l) --> NO3-(aq) + 2H+(aq)

NO2-(aq) + H2O(l) --> NO3-(aq) + 2H+(aq) + 2e-

multiply by 3

and,

Cr2O7^2-(aq) --> 2Cr3+(aq)

Cr2O7^2-(aq) --> 2Cr3+(aq) + 7H2O(l)

Cr2O7^2-(aq) + 14H+(aq) --> 2Cr3+(aq) + 7H2O(l)

Cr2O7^2-(aq) + 14H+(aq) + 6e- --> 2Cr3+(aq) + 7H2O(l)

add both equations,

3NO2-(aq) + 3H2O(l) --> 3NO3-(aq) + 6H+(aq) + 6e-

Cr2O7^2-(aq) + 14H+(aq) + 6e- --> 2Cr3+(aq) + 7H2O(l)

-------------------------------------------------------------------------------

3NO2-(aq) + Cr2O7^2-(aq) + 8H+(aq) --> 3NO3-(aq) + 2Cr3+(aq) + 4H2O(l)

is net-balanced equation

Part B)

BrO3-(aq) --> Br2(l)

2BrO3-(aq) --> Br2(l)

2BrO3-(aq) --> Br2(l) + 6H2O(l)

2BrO3-(aq) + 12H+(aq) --> Br2(l) + 6H2O(l)

2BrO3-(aq) + 12H+(aq) + 10e- --> Br2(l) + 6H2O(l)

multiply by 2

and,

N2H4(aq) --> N2(g)

N2H4(aq) --> N2(g) + 4H+(aq)

N2H4(aq) --> N2(g) + 4H+(aq) + 4e-

multiply by 5

4BrO3-(aq) + 24H+(aq) + 20e- --> 2Br2(l) + 12H2O(l)

5N2H4(aq) --> 5N2(g) + 20H+(aq) + 20e-

------------------------------------------------------------------------

4BrO3-(aq) + 5N2H4(aq) + 4H+(aq) --> 2Br2(l) + 5N2(g) + 12H2O(l)

Is the net balanced equation