(b) Which will contain the greater number of moles of sodium ion:...

Question

(b) Which will contain the greater number of moles of sodium ion:
20.0 mL of 0.15 M NaHCO3 or 15.0 mL of 0.04 M Na2S?

Accepted Answer

Hey everyone, we're asked to identify the solution with the higher concentration of potassium ions. Starting off with a we have 30 mL of our potassium hydroxide. We can go ahead and convert this into leaders and we know that we have 10 to the third milliliters per one leader. Next continuing on with our dimensional analysis, We're going to multiply this by our 0.10 moller which is going to be moles of potassium hydroxide over leaders of potassium hydroxide. Now to look at our multiple ratios, we know that one mole of potassium hydroxide contains one mole of our potassium ions. Now, when we calculate this out and cancel out all our units, we end up with three times 10 to the negative third mole of potassium ions. Now looking at B we have 20 ml of potassium carbonate. Again we want to convert this into leaders and we know that we have 10 to the third milliliters per one leader. Next we're going to multiply it by 0.5 mol. A potassium carbonate over leaders of potassium carbonate. And looking at our multiple ratios, we know that one mole of potassium carbonate contains two mol of our potassium ions. And when we calculate this out and cancel out all our units, we end up with two times 10 to the negative third mole of potassium ions. Now comparing these two values, the solution with the higher concentration of potassium ions is going to be our 30 mL Of 0.10 moller potassium hydroxide. Now I hope that made sense. And let us know if you have any questions.

Watch next