This is an oxidation-reduction (redox) reaction:
Al0 - 2 e- → AlII (oxidation)
2 NIII - 4 e- → 2 NV (oxidation)
CrVI + 6 e- → Cr0 (reduction)
Al is a reducing agent, Cr(NO3)2 is a reducing agent, Cr(NO3)2 is an oxidizing agent.
Input interpretation
Cr(NO3)2 + Al → Al(NO3)2 + Cr
Aluminum chromium
Balanced equation
Balance the chemical equation algebraically:
Cr(NO3)2 + Al → Al(NO3)2 + Cr
Add stoichiometric coefficients, c1, to the reactants and products:
c1Cr(NO3)2 + c2Al → c3Al(NO3)2 + c4Cr
Set the number of atoms in the reactants equal to the number of atoms in the products for Cr, N, O and Al:
Cr: c1 = c4
N: 2c1 = 2c3
0: 6c1 = 6c3
Al: c2 = c3
Since the coefficients are relative quantities and underdetermined, choose a coefficient to set arbitrarily. To keep the coefficients small, the arbitrary value is ordinarily one. For instance, set c1 = 1 and solve the system of equations for the remaining coefficients:
c1 = 1
c2 = 1
c3 = 1
c4 = 1
Substitute the coefficients into the chemical reaction to obtain the balanced
equation:
Answer:
Cr(NO3)2 + Al → Al(NO3)2 + Cr
