Question

1.a. Complete and balance the following equation for a reaction that occurs in basic aqueous solution.

                                           Cr(OH)_3(s)   +   Br_2(aq)     →     CrO₄^2-_(aq)   +   Br^-_(aq)

b. Identify the oxidizing agent. Explain your choice.

c. Which substance undergoes reduction? How do you know?

Answer 1

Ans 1 :

Start balancing the equation writing the oxidation and reduction reactions seperately.

Then balance all other atoms except hydrogen and oxygen.

Then balance hydrogen and oxygen by adding protons and water molecules respectively.

Balance the charges and add the reactions and simplify to get the final balanced reaction as :

2Cr(OH)3 + 3Br2 + 10OH^- = 2CrO₄^2- + 6Br^- + 8H₂O

b) Since Cr has got oxidised , so bromine (Br2) is the oxidizing agent.

c) Bromine has undergone reduction because its oxidation state has changed from 0 to -1.