Balance each of the following redox reactions occurring in acidic aqueous solution.Express your answer as a chemical equation. Identify all of the phases in your answer.
Zn(s) + Na(aq)-> Zn2+(aq)+Na(s)
Cl-(aq) + 2NO3-(aq)->NO(g)+Cl2(g)
I figured out the Zinc problem, but still need some help with the other one.
gottem' both. thanks anyway. I'm sure I'll have more questions on down the road.
To balance redox reactions occurring in acidic aqueous solution, you need to follow these steps:
1. Identify the oxidation states of all elements involved in the reaction.
2. Write separate half-reactions for the oxidation and reduction processes.
3. Balance the atoms in each half-reaction.
4. Balance the charges in each half-reaction by adding electrons.
5. Multiply each half-reaction by an appropriate factor so that the number of electrons gained in the reduction half-reaction is equal to the number of electrons lost in the oxidation half-reaction.
6. Combine the half-reactions and cancel out any common species on opposite sides of the arrow.
7. Check that the number of atoms and charges are balanced on both sides of the equation.
8. Add H+ ions to balance the hydrogen atoms.
9. Add H2O molecules to balance the oxygen atoms.
10. Multiply each half-reaction if necessary to make the number of ions equal.
Now let's balance each of the given redox reactions:
1. Zn(s) + Na+(aq) -> Zn2+(aq) + Na(s)
This reaction does not involve a redox process because both the oxidation and reduction states of the elements remain the same. Hence, there is no need to balance it in terms of redox.
2. Cl-(aq) + 2NO3-(aq) -> NO(g) + Cl2(g)
Step 1: Assign oxidation states:
Cl- = -1
NO3- = -1 (for N), -2 (for each O)
NO = +2 (for N), -2 (for O)
Cl2 = 0 (since it's a diatomic element)
Step 2: Write the separate half-reactions:
Oxidation half-reaction: Cl- -> Cl2
Reduction half-reaction: NO3- -> NO
Step 3: Balance the atoms in each half-reaction:
Oxidation half-reaction: 2Cl- -> Cl2
Reduction half-reaction: 2NO3- -> NO
Step 4: Balance the charges by adding electrons:
Oxidation half-reaction: 2Cl- -> Cl2 + 2e-
Reduction half-reaction: 2NO3- + 4e- -> 2NO
Step 5: Multiply each half-reaction by an appropriate factor:
Oxidation half-reaction: 2Cl- -> Cl2 + 2e-
Reduction half-reaction: 2NO3- + 4e- -> 2NO
Step 6: Combine the half-reactions:
2Cl- + 2NO3- + 4e- -> 2NO + Cl2 + 2e-
Step 7: Cancel out the electrons on both sides of the equation:
2Cl- + 2NO3- -> 2NO + Cl2
Step 8: Add H+ ions to balance hydrogen:
2Cl- + 2NO3- + 4H+ -> 2NO + Cl2 + 2H2O
Step 9: Add H2O molecules to balance the oxygen atoms:
2Cl- + 2NO3- + 4H+ -> 2NO + Cl2 + 2H2O
Step 10: Multiply each half-reaction if necessary:
2Cl- + 6NO3- + 12H+ -> 6NO + 2Cl2 + 6H2O
Therefore, the balanced equation for the given redox reaction is:
2Cl- + 6NO3- + 12H+ -> 6NO + 2Cl2 + 6H2O
The phases of the species are denoted as follows:
s - solid
(aq) - aqueous
g - gas
To balance redox reactions in acidic solutions, follow these steps:
1. Write the unbalanced equation for the redox reaction.
For the first reaction:
Zn(s) + Na(aq) -> Zn2+(aq) + Na(s)
For the second reaction:
Cl-(aq) + 2NO3-(aq) -> NO(g) + Cl2(g)
2. Identify the atoms undergoing oxidation and reduction.
In the first reaction:
- Zn is being oxidized from 0 to +2.
- Na is being reduced from +1 to 0.
In the second reaction:
- Cl is being oxidized from -1 to 0.
- NO3 is being reduced from +5 to +2.
- There is no change in oxidation state for NO.
3. Balance the atoms undergoing oxidation and reduction.
In the first reaction:
- Multiply the reduction half-reaction by 2 to balance the number of electrons transferred.
- Multiply the entire second half-reaction by 2 to balance the number of Na atoms.
2Na(aq) + 2e- -> 2Na(s)
Zn(s) -> Zn2+(aq) + 2e-
The balanced equation for the first reaction is:
Zn(s) + 2Na(aq) -> Zn2+(aq) + 2Na(s)
In the second reaction:
- Multiply the reduction half-reaction by 5 to balance the number of electrons transferred.
- Multiply the entire oxidation half-reaction by 3 to balance the number of Cl atoms.
5Cl-(aq) -> Cl2(g) + 5e-
3NO3-(aq) + 5e- -> NO(g) + 3O2(g)
The balanced equation for the second reaction is:
3Cl-(aq) + 2NO3-(aq) -> NO(g) + Cl2(g) + 3O2(g)
Note: The phases of the substances in the balanced equations should be included (s for solid, aq for aqueous, g for gas).