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`

Answer

(i) B is limiting (ii) A is limiting
(iii) stoichiometric mixture -No (iv) B is limiting
(V) A is limiting

Explanation

A limiting reagent determines the extent of a reaction ,It is the reactant which is the first to get consumed during a reaction , thereby the reaction to stop and limiting the amount of products formed .
(i) Accoding to the given reaction , 1 aatom of A reacts with 1 molecule of B. THus ,200 molecules of B will react with 200 atoms of A , thereby leaving 100 atoms of A unused . Hence ,B is the limiting reagent .
(ii) Accoding to the reaction ,1 mol of A reacts with 1 mol of B , THus 2 mol of A will react with with only 2 mol of B.As a result , 1 mol of A will not be consumed .Hence , A is the limiting reagent .
(iii) Accoding to the given reaction , 1 atom of A combines with 1 mole cule of B .Thus all 100 atoms of A will combine with all 100 molecule of B. Hence , the mixture is stoichiometric where ni limiting reagent is present .
(iv0 1 mol of atom A combines with 1 mol of molecule B. THus ,2.5 mol of B will combine with only 2.5 mol of A .As a result ,2.5 mol of A will be left as such ,Hence ,B is the limiting reagent .
(v0 Accoding to the reacation , 1 mol of atom A combines with 1 mol of molesule B . Thus, 2.5 mol of A will comine with only 2.5 mol of B. and The remaining 2.5 mol of B. will be left as such .Hence ,A is the limiting reagent .