Question

10. The reactant which is entirely consumed in reaction is known as limiting reagent. In the reaction 2A + 4B 3C + 4D, when 5 moles of A react with 6 moles of B. Then i. Which is the limiting reagent ? ii. Calculate the amount of C formed ?

Answer 1

1. As given the example, 2 moles of A requires 4 moles of B for a reaction to occur.

Therefore, moles of B required for 5 moles of A = 5 moles of A X 4 moles of B/ 2 moles of A. But, as given in the example, we have only 6 moles of B. This means that B is the limiting reagent.

2. Amount of C is decided by B. 4 moles of B gives 3 moles of C. Therefore, 6 moles of B= 6 moles of B X 3 moles of C /4 moles of B = 4.5 moles of C. 

Answer 2

Answer:2A + 4B —> 3C + 4D

Here, 2 moles of A reacts with 4 moles of B. Therefore,

5 moles of A reacts with 4/2x5 =10 moles of B.

But,

we have 6 moles of ‘B’

(i) It means ‘B’ is limiting reactant

(ii) 4 moles of ‘B’ gives 3 moles of C.

Hence, 6 moles of ‘B’ gives

3/4 *6 = 18/4 = 9/2 = 4.5 moles of C.