Consider the following substances: NaMnO₄, a soluble purple solid; AgMnO₄, an insoluble purple solid; NaCl, a soluble white solid; AgCl, an insoluble white solid. Which of the following would be observed when 1.0 moles of AgCl and 0.5 moles of NaCl are mixed in one litre of water? A) Purple solid and colorless solution, B) purple solid and purple solution, C) white solid and colorless solution, D) no solid and purple solution, or E) no solid and colorless solution.
The question is asking us what we would see if we mixed some silver chloride, AgCl, and some sodium chloride, NaCl, in water. We’ve been told that silver chloride is insoluble and white in its solid form and that sodium chloride, also a white solid, is soluble. When a solvent isn’t stated, we can assume that soluble or insoluble refer to solubility in water, which is exactly the solvent we have here. So we know that when we add our sodium chloride, it’ll dissolve. And when we add the silver chloride, it’ll just sink to the bottom. Sodium chloride and silver chloride share the same anion. And they’re very stable in each other’s company. So there’s no reaction.
And the last piece of information we need is that generally speaking, unless there’s a specific reaction, white solids will dissolve to give colorless solutions. Therefore, our final observation will be that of one mole of silver chloride, a white powder at the bottom of our container, with the solution of sodium chloride above it being completely colorless.
This corresponds with option C, white solid and colorless solution.