Task

Chemical analysis. Four unlabelled tubes contain solutions of sodium chloride, sodium iodide, sodium carbonate and sodium sulfate. Only dilute nitric acid, barium chloride, silver nitrate and ammonia solution are available. The sodium chloride solution was made by dissolving 1.17 g of the salt. 1) Write the reactions (or absence of reaction) of the four anions with silver nitrate, the colours of the precipitates and their behaviour towards nitric acid; calculate the mass of precipitate in the sodium chloride tube. 2) Write equations showing which anions precipitate with barium chloride and how nitric acid distinguishes these precipitates. 3) Draw up an economical step-by-step scheme to identify all four substances and write the equation for each step. 4) Explain with an equation how ammonia solution distinguishes silver chloride from silver iodide. For every part, show the method (reaction equations, formulas, reasoning) and all calculations step by step.