Question

A chemical reaction: $A+B\to AB$, B is acting as a limiting reagent then choosing the correct option. The limiting reagent is?
(A) A=50 atm, B= 100 atm
(B) A= 100 atm, B= 200 atm
(C) A= 50 atm, B=30 atm
(D) A= 50 atm, B= 200 atm

Answer 1

Limiting reagents are the substances which are entirely consumed in the reaction and are responsible for the formation of product in the reaction. The limiting reagent decides the amount of product formed.

Complete step by step solution:
Limiting reagents are also referred to as limiting agents. According to the stoichiometry of a reaction a fixed amount or reactants is required for the completion of the reaction. These reactants will determine when the reaction will stop.
Given in the question:
A chemical reaction: $A+B\to AB$
B is the limiting reagent it means that B will decide when the reaction will stop and the pressure of A will be greater than the pressure of B hence the only correct answer is A= 50 atm and B=30 atm.

Hence the correct answer is, option C.

Additional information:
We can find the limiting reagent by two ways:
By looking at the number of moles of each reactant.
By calculating and comparing the amount of the product which is produced by each reactant.

Note: While solving this type of question where no mathematical value is given we usually eliminate the answers according to the given question. As in this question it is mentioned that B is the limiting reagent and we know that it pressure would be low so we will search for the option in which the given value for pressure will be less for B and higher for A.