Question

The equation X + Y 2Z has the rate law equation shown below. Which of the following statements best describes the relationship of X on the rate of the reaction? rate = k[X]2[Y]

Changing X has no effect on the reaction rate.
Doubling X causes the reaction rate to quadruple.
Dividing X by two causes the reaction rate to be cut in half.
Multiplying X by three also increases the reaction rate by three times.

Answer 1

The order of the reaction with respect to X is 2.
The statements given ;
1. As Concentration of X is in the rate law equation , changing X will have an effect on the rate of the equation.
2. Rate is proportional to X^2
So if concentration of X is doubled, then rate proportional to (2X)^2 = 4X^2
Rate therefore quadruples when X is doubled
This statement is correct
3. If we divide X/2 then the effect to the rate is (X/2)^2 = X/4 . This will reduce the rate by quarter not half . This statement is wrong.
4. If we multiply by 3
Then rate proportional to (3X)^2 = 9X^2
Rate increases by 9 times. This statement is wrong