Methyl salicylate (oil of wintergreen), CBH,Os, is prepared by heating 2-hydroxy
ID: 573021 • Letter: M
Question
Methyl salicylate (oil of wintergreen), CBH,Os, is prepared by heating 2-hydroxybenzoi acid, C,H, Os, with methanol C H,OH as described by the reaction equation: 5) Here, 5.42 g of 2-hydroxybenzoic acid is reacted with 14.2 g of methanol. (Hint: This is a limiting reactant problem up to this point where two theoretical calcula tions are performed to compute the smallest mass of product that can possibly be obtained) At the conclusion of the reaction, an actual yield of 1.65 grams of methyl salicylate, CaH, O3, is obtained. What is the fraction yield? percentage yield?Explanation / Answer
Percent yield = (Actual yield/theoreical yield) ×100
fraction yield = percent yield/100
Theoretical yield is calculated as follows
C7H6O3 + CH3OH - - - - - > C8H8O3 + H2O
stoichiometrically, 1mole of C7H6O3 reacting with 1mole of CH3OH to give 1mole of C8H8O3
No of mole of C7H6O3 = 5.42g/138.118g/mol = 0.03924mol
No of mole of CH3OH = 14.2g/32.042g/mol =0.44316mol
So, the limiting reagent is C7H6O3
0.03924 mole of C7H6O3 give 0.03924mol of C8H8O3
Molar mass of C8H8O3 = 152.144g/mol
mass of C8H8O3 should produce = 0.03924mol × 152.144g/mol =5.9701g
Theoretical yield = 5.9701g
percent yield = (1.65g/5.9701g)×100 = 27.64%
fraction yield = 27.64/100 = 0.2764