In a reaction
`A+B_(2) rarr AB_(2)`
Identify the limiting reagent, if any, in the following reaction mixtures.
a. `300 "atoms"` of `A+ 200` molecules of `B`
b. `2 mol A+3 mol B`
c. `100 "atoms"` of `A+100` molecules of `B`
d. `5 mol A+2.5 mol B`
e. `2.5 mol A + 5 mol B`

Explanation

(i) According to the given reaction `A + B_(2) to AB_(2)`, one atom of A reacts with one molecule of B. 300 atoms of A will require 300 molecules of B for complete reaction. Since, the molecules of B present are only 200, it is short of 100 molecules. Thus, A is in excess. Therefore, B is the limiting reagent.
(ii) 1 mol of 4 reacts with 1 mol of B.
`therefore` 2 mol of A will react with 2 mol of B. Since, 3 mol of B are present, it is in excess. Thus, A is the limiting reagent.
(iii) 100 atoms of A will completely react with 100 molecules of B. Thus, both will get consumed . Hence, there is no limiting reagent in this case.
(iv) 2.5 mol of B will react with 2.5 mol of A. Thus, A will be left in excess. Therefore, B is the limiting reagent.
(v) 2.5 mol of A will react with 2.5 mol of B. Thus, B will be left in excess. Therefore, A is the limiting reagent.