The bromination of acetone is acid-catalyzed.

Question

CH3COCH3 + Br2 CH3COCH2Br + H+ + Br -
The rate of disappearance of bromine was measured for several different concentrations of acetone, bromine, and H+ ions at a certain temperature.
[CH3COCH3] [Br2] [H+] rate of disappearance of Br2 (M/s)
0.30 0.050 0.050 5.7 10-5
0.30 0.10 0.050 5.7 10-5
0.30 0.050 0.10 1.2 10-4
0.40 0.050 0.20 3.1 10-4
0.40 0.050 0.050 7.6 10-5

(a) What is the rate law for the reaction?
(b) Determine the rate constant. answer in M·s

Answer 1

You really need to tell us what you don't understand about this.
To get you started, we can look at reaction 1 and reaction 2. Acetone is same concn, Br2 is different, H^+ is same and rate is same. So the only difference in concn is Br2 (change from 0.05 to 0.10) but rate remains the same. What does that tell you about the order with respect to (Br2)?
Then compare reaction 1 with reaction 3. Acetone is same, Br2 is same, H^+ is different (0.05 vs 0.1). That should give you the exponent (order) for (H^+). If I didn't goof that will be 1. Clarify your thoughts in a repost if this doesn't help.