CHEM 1212 Module Nine Sample Exam Page 5 Name:______________

Part G: Reaction Mechanisms 20 points

The mechanism for the decomposition of hydrogen peroxide is:

H₂O₂ à 2 OH

H₂O₂ + OH à H₂O + HO₂

HO₂ + OH à H₂O + O₂

If the order of the reaction is first order with respect to hydrogen peroxide and overall the reaction is first order; which step(s) above is(are) the rate determining steps?

Which species are reaction intermediates?

The rate law for the reaction:

BrO₃ ^1- (aq) + 3 SO₃ ^{2 -} (aq) à Br ^1- (aq) + 3 SO₄ ^{2 -} (aq)

is: Rate = k’[BrO₃ ^1-] [ SO₃ ^{2 -}] [ H ¹⁺]

The first step in the mechanism is:

SO₃ ^{2 -} (aq) + H ¹⁺ (aq) -----------> H SO₃ ^{1 -} (aq) FAST

The second step is rate determining. Write a possible second step for the mechanism.