This is an oxidation-reduction (redox) reaction:
2 Br-I - 2 e- → 2 Br0 (oxidation)
2 HI + 2 e- → 2 H0 (reduction)
CaBr2 is a reducing agent, H2O is an oxidizing agent.
Word equation
calcium bromide + water → hydrogen + calcium hydroxide + bromine
Input interpretation
CaBr2 + H2O → H2 + Ca(OH)2 + Br2
Calcium water hydrogen calcium bromine
Bromide hydroxide
Balanced equation
Balance the chemical equation algebraically:
CaBr2 + H2O → H2 + Ca(OH)2 + Br2
Add stoichiometric coefficients, c, to the reactants and products:
CaBr2 + H2O → H2 + Ca(OH)2 + Br2
Set the number of atoms in the reactants equal to the number of atoms in the products for Br, Ca, H and O:
Br: 2c1 = 2cs
Ca: c1 = c4
H: 2c2 = 2c3 + 2c4
O: c2 = 2c4
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=2
c3=1 c4=1
c5=1
Substitute the coefficients into the chemical reaction to obtain the balanced equation:
Answer:
CaBr2 + H2O → H2 + Ca(OH)2 + Br2
