(e)

Ammonium sulfate reacts with aqueous sodium hydroxide as shown by the equation below.
(NH),SO, + 2NaOH 2NH₂ + Na₂SO, + 2H₂O
A sample of ammonium sulfate was heated with 100 cm³ of 0.500 mol dm³ aqueous
sodium hydroxide. To ensure that all the ammonium sulfate reacted, an excess of sodium
hydroxide was used. Heating was continued until all the ammonia had been driven off as
a gas. The unreacted sodium hydroxide remaining in the solution required 27.3 cm³ of
0.600 mol dm³ hydrochloric acid for neutralization.
(i)

Calculate the original number of moles of NaOH in 100 cm³ of 0.500 mol dm
aqueous sodium hydroxide.