Question

What is the molar concentration of Na⁺ ions in 0.015 M solutions of the following sodium salts in water?

(a) NaBr

(b) Na₂SO₄

(c) Na₃PO₄

Answer 1

PART-A

NaBr===> Na+ + Br-

to calculate the concentration of Na(+) ions in the final solution, take 1 times the inital concentration

0.015*1 = 0.015M

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PART-B

Na2SO4 ===========>2Na+ +SO4(3-)

calculate the concentration of Na(+) ions in the final solution, take 2 times the inital concentration

0.015*2 = 0.03M

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PART-C

Na3PO4 ----> 3 Na(+) + PO4(-3)

Now, you are starting out with a 0.015 M solution of Na3PO4, but when you dissolve the Na3PO4 into solution there are 3 Na(+) ions made for every Na3PO4 molecule that dissolves

Therefore to calculate the concentration of Na(+) ions in the final solution, take 3 times the inital concentration

. 0.015* 3 = 0.045M in Na(+)

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