Question

In a particular redox reaction, NO2

Answer 1

1. Balance elements in the equation other than O and H.

NO2- ---> NO3-

Ag+- --> Ag(s)

2. Balance the oxygen atoms by adding the appropriate number of water (H2O) molecules to the opposite side of the equation.

H2O + NO2- ---> NO3-

3. Balance the hydrogen atoms (including those added in step 2 to balance the oxygen atom) by adding H+ ions to the opposite side of the equation.

H2O + NO2- ---> NO3- + 2H+

4.Add up the charges on each side. Make them equal by adding enough electrons (e-) to the more positive side. (Rule of thumb: e- and H+ are almost always on the same side.)

Ag+ + e- --> Ag(s)

H2O + NO2- ---> NO3- + 2H+ +2e-

5. The e- on each side must be made equal; if they are not equal, they must be multiplied by appropriate integers (the lowest common multiple) to be made the same.

2Ag+ + 2e- --> 2Ag(s)

H2O + NO2- ---> NO3- + 2H+ +2e-

6. The half-equations are added together, canceling out the electrons to form one balanced equation. Common terms should also be canceled out.

2Ag+ + 2e- H2O + NO2- ---> NO3- + 2H+ +2e- + 2Ag(s)

2Ag+ + H2O + NO2- ---> NO3- + 2H+ + 2Ag(s)

For 2

ClO2- --> ClO4-

Ag+ ---> Ag(s)

1. Balance elements in the equation other than O and H.

ClO2- --> ClO4-

Ag+ --> Ag(s)

2. Balance the oxygen atoms by adding the appropriate number of water (H2O) molecules to the opposite side of the equation.

2H2O + ClO2- --> ClO4-

3. Balance the hydrogen atoms (including those added in step 2 to balance the oxygen atom) by adding H+ ions to the opposite side of the equation.

2H2O + ClO2- --> ClO4- + 4H+

4.Add up the charges on each side. Make them equal by adding enough electrons (e-) to the more positive side. (Rule of thumb: e- and H+ are almost always on the same side.)

Ag+ + e- --> Ag(s)

2H2O + ClO2- --> ClO4- + 4H+ + 4e-

5. The e- on each side must be made equal; if they are not equal, they must be multiplied by appropriate integers (the lowest common multiple) to be made the same.

4Ag+ + 4e- --> 4Ag(s)

2H2O + ClO2- --> ClO4- + 4H+ + 4e-

6. The half-equations are added together, canceling out the electrons to form one balanced equation. Common terms should also be canceled out.

2H2O + ClO2- + 4Ag+ + 4e- --> 4Ag(s)+ClO4- + 4H+ + 4e-

2H2O + ClO2- + 4Ag+ --> 4Ag(s)+ClO4- + 4H+