Case 3 : Percentage Yield,Case 4: Amount / Moles OF Atleast 2 Reactants is given Idea OF Limiting Reagent (LR) and Excess Reagent (ER)

Case 1: Amount / Moles OF only 1 Reactant is given ( JH shortcut to Solve all such Questions)

Concept of Limiting Reagent (LR) ||Excess Reagent (ER)v|| Class Illustrations on LR and ER

Which is limiting reagent in the above case in above question?

The reactant which is entirely consumed in reaction is known as limiting reagent. In the reaction 2A+4Brarr3C+4D , when 5 moles of A react with 6 moles of B, then (a) which is the limiting reagent? (b) calculate the amount of C formed?

Many a time the reaction are carried out when the reactants are not present in the amounts required by a balanced chemical reaction. In such situations, one reactant is in excess over other. The reactant which is present in th lesser amount gets conserved after sometime and after that no further reaction takes place whatever be the amount of other reactant is present .Hence, the reactant which gets consumed , limits the amount of products formed and is therefore called limiting reagent. To determine the limiting reagent find the value of phi which is the ratio of (given) mole of a substance to the stoichiometric coefficient of that substance . The limiting reagent is the reagent which has minimum value of phi . The insecticide DDT is made by the reaction CClCHO("Chloral")+2C_(6)H_(5)Cl (chlorobenzene) rarr (ClC_(6)H_(4))_(2) CHCCl_(3)(DDT)+H_(2)O If 100 pound (lb) of chlorobenzene , how much DDT would be formed? (Assume the reaction goes to completion without side reactions or losses) [1 lb =453.6 g]

Limiting reactant: Urea [(NH_(2))_(2) CO] used as ferlilzer as animal feed, and in polymer industry, is prepared by the reaction between ammonia and carbon dioxide: 2NH_(3)(g) + CO_(2) (g) rarr (NH_(2))_(2) CO(aq.) + H_(2) O(1) In one process , 637.2g of NH_(3) is allowed to react with 11.42g of CO_(2) (i) Which of the two reactants is the limiting reactant? (ii) Calculate the mass of (NH_(2))_(2) CO formed? (iii) How much of the excess reagent (in grams) is left at the end of the reaction? Strategy: (i) Since we cannot tell by inspection which of the two recantants is the limiting reacant, we have to procced by first converting their masses into number of moles. Take each reactnat in turn and ask how many moles of product (urea) would be obtained if each were completely consumed. The reactant that gives the smaller number of moles of producet is the limiting reactant. (ii) Convert the moles of product obtained to grams of product. (iii) From the moles of product, calculate to grams fo excess reactant needed int he reaction. Then subtract this qunitity from the grams of the reactant available to find the quanity of the excess reactant remaining.

Gravimetric Analysis and Mole Concept, Concept of Limiting reagent and Yield of a Chemical Reaction