Balance the following oxidation-reduction reactions, which occur in acidic solution, using the half-reaction method. (Use the lowest possible coefficients. Include states-of-matter under the given conditions in your answer.)
(a) Cu(s) + NO3‾(aq) → Cu2+(aq) + NO(g)
asd
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To balance the given oxidation-reduction reaction in acidic solution using the half-reaction method, we'll follow these steps:
Step 1: Assign oxidation numbers.
Step 2: Split the reaction into half-reactions.
Step 3: Balance the atoms other than hydrogen and oxygen.
Step 4: Balance the oxygen atoms by adding water molecules.
Step 5: Balance the hydrogen atoms by adding hydrogen ions (H+).
Step 6: Balance the charges by adding electrons.
Step 7: Equalize the number of electrons transferred in both half-reactions.
Step 8: Combine the half-reactions to cancel out the electrons.
Step 9: Check the atom and charge balance.
Step 10: Verify the balanced equation.
Let's go through each step:
Step 1: Assign oxidation numbers.
Cu(s) has an oxidation number of 0.
NO3‾(aq) has an oxidation number of -1.
Cu2+(aq) has an oxidation number of +2.
NO(g) has an oxidation number of +2.
Step 2: Split the reaction into half-reactions.
Cu(s) → Cu2+(aq)
NO3‾(aq) → NO(g)
Step 3: Balance the atoms other than hydrogen and oxygen.
There is one Cu atom on both sides.
There is one N atom on both sides.
There are three O atoms on the left and one on the right.
Step 4: Balance the oxygen atoms by adding water molecules.
NO3‾(aq) → NO(g) + 3 H2O(l)
Step 5: Balance the hydrogen atoms by adding hydrogen ions (H+).
NO3‾(aq) + 4 H+(aq) → NO(g) + 3 H2O(l)
Step 6: Balance the charges by adding electrons.
NO3‾(aq) + 4 H+(aq) + 3 e- → NO(g) + 3 H2O(l)
Step 7: Equalize the number of electrons transferred in both half-reactions.
Cu(s) → Cu2+(aq) + 2 e-
Step 8: Combine the half-reactions to cancel out the electrons.
2 Cu(s) + 2 NO3‾(aq) + 8 H+(aq) → 2 Cu2+(aq) + 2 NO(g) + 6 H2O(l)
Step 9: Check the atom and charge balance.
Atoms: 2 Cu, 2 N, 8 O, 8 H on both sides
Charge: 0 charge on both sides
Step 10: Verify the balanced equation.
2 Cu(s) + 2 NO3‾(aq) + 8 H+(aq) → 2 Cu2+(aq) + 2 NO(g) + 6 H2O(l)
Therefore, the balanced equation is:
2 Cu(s) + 2 NO3‾(aq) + 8 H+(aq) → 2 Cu2+(aq) + 2 NO(g) + 6 H2O(l)