At 518^oC the rate of decomposition of a sample of gaseous acetaldehyde initially at a pressure of 363 Torr, was 1.00 Torr s^–1 when 5% had reacted and 0.5 Torr s^–1 when 33% had reacted. The order of the reaction is

Which of the following are Lewis acids?

An aqueous solution contains 0.10 M H₂S and 0.20 M HCl. If the equilibrium constants for the formation of HS^– from H₂S is 1.0 $$\times$$ 10^–7 and that of S^2- from HS^– ions is 1.2 $$\times$$ 10^–13 then the concentration of S^2- ions in aqueous solution is :

An aqueous solution contains an unknown concentration of Ba²⁺. When 50 mL of a 1 M solution of Na₂SO₄ is added, BaSO₄ just begins to precipitate. The final volume is 500 mL. The solubility product of BaSO₄ is 1 $$\times$$ 10^–10. What is the original concentration of Ba²⁺?