Question

Multiple choice: Soap in Hard Water. What is the correct solution and why?

Answer 1

Surely it is sample `A`?

Explanation:

You assess water hardness, and the Table gives you the means to do this. Sample `A` requires the most soap to give a decent lather. It also has the greatest boiling point, and the most precipitate when treated with `Ag^+` (i.e. the greatest concentration of `HO^-`).

I am willing to bet that if they had tabulated `pH` of each sample, sample `A` would have had the highest `pH`.