Balance the following equation by oxidation number method in acidic medium :
(i) Fe^2+ + Cr2O7^2- gives Cr^3+ + Fe^3+
Please Give Me Answer Fast!
Answers
Explanation:
Step 1: Write the unbalanced ionic equation,
Fe
2+
(aq)+Cr
2
O
7
2−
(aq)⟶Fe
3+
(aq)+Cr
3+
(aq)
Step 2: Write separate half-reactions for the oxidation and the reduction processes. Determine the oxidation numbers first, if necessary,
Fe
+2
→Fe
+3
Cr
+6
→Cr
+3
step 3: Balance the atoms in the half-reactions other than hydrogen and oxygen. In the oxidation half-reaction above, the iron atoms are already balanced. The reduction half-reaction needs to be balanced with the chromium atoms,
Step 4: Balance oxygen atoms by adding water molecules to the appropriate side of the equation. For the reduction half-reaction above, seven H
2
O molecules will be added to the product side,
Cr
2
O
7
2−
(aq)→2Cr
3+
(aq)+7H
2
O(l)
Now the hydrogen atoms need to be balanced. In an acidic medium, add hydrogen ions to balance. In this example, fourteen H
+
ions will be added to the reactant side.
Step 5: Balance the charges by adding the electrons,
6Fe
2+
(aq)+Cr
2
O
7
2−
(aq)⟶6Fe
3+
(aq)+2Cr
3+
(aq)+7H
2
O.