The results given in the below table were obtained during kinetic studies of the following reaction
2A + B → C + D
X and Y in the given table are respectively :

Solution

Chemistry ma’am · 5 steps

First find each order from rows I, II and III, then use the rate law to fill in X and Y.

1. Order in B. From I to II, [A] stays at 0.1 and [B] doubles. The rate goes from 6.00 × 10⁻³ to 2.40 × 10⁻², which is 4 times. Since 2² = 4, the reaction is second order in B.
2. Order in A. From I to III, [B] stays at 0.1 and [A] doubles. The rate goes from 6.00 × 10⁻³ to 1.20 × 10⁻², which is 2 times, so the reaction is first order in A. Experiment I then gives k = (6.00 × 10⁻³)/(0.1 × (0.1)²) = 6 L² mol⁻² min⁻¹.

   Rate = 6 [A][B]²

3. Find X. Experiment IV gives 7.20 × 10⁻² = 6 × X × (0.2)² = 0.24X. So X = 0.072/0.24 = 0.3.
4. Find Y. Experiment V gives 2.88 × 10⁻¹ = 6 × 0.3 × Y² = 1.8Y². So Y² = 0.16 and Y = 0.4.
5. So. X = 0.3 and Y = 0.4, which is option (a).

The idea to keep. Find the order of each reactant from a pair of rows where only that concentration changes. Once you know k and both orders, any missing concentration comes straight from the rate law.

Answer from the NTA final answer key. Solution by PrepWiser.