Question

The following results were obtained in the gas phase reaction between nitric oxide and oxygen at a given temperature.

• A. 3 and 2
• B. 2 and 2
• C. 2 and 1
• D. 3 and 0
• E. 3 and 1

Hint:

To determine reaction order, vary the concentration of one reactant while keeping others constant and observe the change in rate.

Answer 1

Answer: (E)

Step 1: From the data, doubling the concentration of \([NO]\) from 0.30 to 0.60 (while keeping \([O_2]\) constant) results in quadrupling the rate, indicating a second-order dependence on \([NO]\). 
Step 2: Increasing \([O_2]\) concentration from 0.30 to 0.60 (while keeping \([NO]\) constant) doubles the rate, indicating a first-order dependence on \([O_2]\). 
Step 3: The total order of the reaction is \(2 (NO) + 1 (O_2) = 3\). 
Step 4: Thus, the total order is 3, and the order in \([O_2]\) is 1.