Zn + VO3 ^- --> Zn ^2+ + V^+3
Fe ^2+ + H2O2 + OH- --> Fe (OH) 3
V2O5 + I- + H^+ --> VO2 + I2 + H20
P + H+ + NO3- + H2O -->'NO + H3PO4
RedOX REACTIONS
Redox reactions, also known as oxidation-reduction reactions, involve the transfer of electrons between reactants. In these reactions, one species loses electrons (undergoes oxidation) while another species gains electrons (undergoes reduction).
To determine whether a reaction is a redox reaction and to identify the oxidizing and reducing agents, you need to follow these steps:
1. Assign oxidation numbers: Begin by assigning oxidation numbers to each element in the reaction. Oxidation numbers represent the hypothetical charge that an atom would have if all its bonds were 100% ionic.
2. Identify the species undergoing oxidation and reduction: Look for elements whose oxidation numbers change from the reactant side to the product side. The species with an increase in oxidation number is being oxidized, while the species with a decrease in oxidation number is being reduced.
3. Determine the oxidizing and reducing agents: The oxidizing agent is the species that accepts electrons and gets reduced, while the reducing agent is the species that donates electrons and undergoes oxidation.
Let's analyze the given chemical equations:
1. Zn + VO3^- → Zn^2+ + V^+3
- Assign oxidation numbers: Zn(0), V(+5), O(-2)
- Zinc (Zn) is oxidized since its oxidation number increases from 0 to +2.
- Vanadium (V) is reduced since its oxidation number decreases from +5 to +3.
- The oxidizing agent is VO3^-, and the reducing agent is Zn.
2. Fe^2+ + H2O2 + OH^- → Fe(OH)3
- Assign oxidation numbers: Fe(+2), O(-2), H(+1)
- Iron (Fe) is oxidized from +2 to +3.
- Hydrogen peroxide (H2O2) acts as an oxidizing agent since it causes the oxidation of Fe.
- The reducing agent is Fe^2+.
3. V2O5 + I^- + H^+ → VO2 + I2 + H2O
- Assign oxidation numbers: V(+5), O(-2), I(-1), H(+1)
- Vanadium (V) is reduced from +5 to +4.
- Iodine (I) is oxidized from -1 to 0 (I2).
- The oxidizing agent is H^+, and the reducing agent is V2O5.
4. P + H^+ + NO3^- + H2O → NO + H3PO4
- Assign oxidation numbers: P(0), H(+1), N(+5), O(-2)
- Phosphorus (P) is oxidized from 0 to +5.
- Nitrate (NO3^-) acts as an oxidizing agent since it causes the oxidation of P.
- The reducing agent is P.
Remember, the key to solving redox reactions is identifying changes in oxidation numbers and determining which species are being oxidized or reduced.