Question

What is the molar concentration of phosphate ions in a 0.350 mli3po4 solution?

Answer 1

Answer : The molar concentration of phosphate ions in lithium phosphate solution is, 0.350 M

Explanation : Given,

Concentration of lithium phosphate = 0.350 M

As lithium phosphate dissolve in water, it dissociates into lithium ions and phosphate ions.

The balanced reaction will be,

$Li_3PO_4\rightarrow 3Li^++PO_4^{3-}$

From the balanced reaction we conclude that,

As, mole ratio of $Li_3PO_4$, $Li$ and $PO_4^{3-}$ is, 1 : 3 : 1

So,

The molar concentration of lithium ion = 3 × 0.350 M = 1.05 M

The molar concentration of phosphate ion = 0.350 M

Therefore, the molar concentration of phosphate ion is, 0.350 M

Answer 2

When answering the above question or problem, first thing to realize is that the dissolution of the Na3PO4 can be written in a format that may be easier to see what is happening here. 

Na3PO4 ----> 3 Na(+) + PO4(-3) 

Now, you are starting out with a 0.35 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. 0.35 * 3 = 1.05 M in Na(+)