14.6 g of diethyl ethanedioate (diethyl oxalate, $C X_{2} O X_{4} (C X_{2} H X_{5}) X_{2}$ , molar mass $146 g mo l^{- 1}$ ) is boiled with excess aqueous NaOH until hydrolysis is complete. The disodium ethanedioate formed ( $Na X_{2} C X_{2} O X_{4}$ , molar mass $134 g mo l^{- 1}$ ) is isolated in $85%$ yield. What mass of it is obtained, in grams, to one decimal place?

Numerical answer type, tolerance 0.05.

Answer: 11.4

Moles of ester

= 14.6/146 = 0.100

mol. Each ester gives one oxalate (together with 2 ethanol): theoretical mass

= 0.100 \times 134 = 13.4

g. At

85%

yield, mass

= 13.4 \times 0.85 = 11.39

g, i.e. 11.4 g.