Difficult Rate Law Problem with no same [A] value to get the order for[B]?

Question

2A+B=C+D sry they're not spaced. The last [B] is unknown intentionally.

Experiment Initial[A] Initial[B] Initial Rate of Formation of C(mol/Lmin)

1 .25 .75 4.3 x 10^-4

2 .75 .75 1.3 x 10^-3

3 1.50 1.50 5.3 x 10^-3

4 1.75 x 8.0 x 10^-3

a.Order of reaction for [A] and [B]?

b. rate law and rate constant?

c. What is the reaction mechanism?

Answer 1

Expt 1/2:  A triples, rate triples. First order in A.

Expt 2/3:  A and B both double, rate quadruples.  First order in A and B.

Rate = k[A][B], You can calculate k.

Reaction mechanism is multiple step with the rate-determing step a bimolecular reaction between 1 molecule of A and 1 molecule of B.