Neco Model Questions Vol1 2022 Chemistry Question 31

Oxalic acid \(\mathrm{HOOC-COOH}\) (0.050 mol) is esterified with ethanol (\(\mathrm{C_2H_5OH}\)) in the presence of concentrated \(\mathrm{H_2SO_4}\). The reaction requires 2 mol of ethanol per mol of oxalic acid: \(\mathrm{HOOC-COOH + 2\,C_2H_5OH \rightarrow EtOOC-COOEt + 2\,H_2O}\). Exactly 8.0 g of ethanol is used. After reflux, 6.2 g of diethyl oxalate (\(\mathrm{EtOOC-COOEt}\), \(M = 146.14\ \text{g mol}^{-1}\)) is isolated. The product is then hydrolysed with 0.10 mol of NaOH, yielding oxalic acid which is recovered as 3.2 g solid (\(M = 90.03\ \text{g mol}^{-1}\)). Determine (a) the limiting reagent in the esterification step, (b) the percent yield of diethyl oxalate, and (c) the overall percent recovery of oxalic acid relative to the original amount.