Find the concentration of h+ ions at a ph = 11 and ph = 6. then divide the concentration of h+ ions at a ph = 11 by the of h+ ions at a ph = 6. record your answer in table c. what is the concentration of h+ ions at a ph = 11? mol/l what is the concentration of h+ ions at a ph = 6? mol/l how many fewer h+ ions are there in a solution at a ph = 11 than in a solution at a ph = 6?

The hydrogen ion concentration can be calculated using pH 
pH = -log [H⁺]
when pH is known antilog of pH needs to be calculated
[H⁺] = antilog (-pH)
when pH = 11
[H⁺] = antilog(-11)
[H⁺] = 1 x 10⁻¹¹ mol/L

when pH = 6
[H⁺] = antilog (-6)
[H⁺] = 1 x 10⁻⁶ mol/L

then to find how much fewer H⁺ ions at pH = 11 than when pH = 6, we have to find the ratio.
ratio = (1 x 10⁻¹¹ mol/L) /  (1 x 10⁻⁶ mol/L)
there's 10⁻⁵ lesser H⁺ ions when pH - 11 than when pH - 6

Only one reactant yields 2 or more products. meaning you will only have 1 product and it will break down into 2 or more products. eg. h2o -> h2 + o2

Use a magnet to separate iron, evaporate water, i'm not sure how to separate the other two i'm sorry but good luck