International Chemistry Olympiad · 1974

Problems

Problem 4A mixture contains two organic compounds, A and B, both containing oxygen and miscible in all proportions. Controlled oxidation of this mixture yields a single compound C, which forms an addition compound with $\ce{NaHSO3}$ . The molar mass ratio of this bisulfite adduct to compound C is 2.7931. Burning the mixture of A and B with a stoichiometric amount of air (20 % $\ce{O2}$ , 80 % $\ce{N2}$ by volume) yields a gas mixture of total volume 5.432 dm $^3$ at STP. When bubbled through $\ce{Ba(OH)2}$ solution, the volume decreases by 15.46 %. (a) Identify compounds A, B and C. (b) Calculate the molar ratio of A and B in the initial mixture. ( $A_r(\text{C}) = 12$ , $A_r(\text{O}) = 16$ , $A_r(\text{S}) = 32$ , $A_r(\text{Na}) = 23$ )Solutions: 1