Question

If the reaction of phosphate ion with water is ignored, what is the total concentration of ions in a solution prepared by dissolving 3.00 g of K3PO4 in enough water to make 350. mL of solution?

A) 0.162 M
B) 0.0404M
C) 0.323M
D) 0.0101 M

Answer 1

A) 0.162 M

Step-by-step explanation:

Calculation of the moles of
`K_3PO_4` as:-

Mass = 3.00 g

Molar mass of
`K_3PO_4` = 212.27 g/mol

The formula for the calculation of moles is shown below:

`moles = (Mass\ taken)/(Molar\ mass)`

Thus,

`Moles= (3.00\ g)/(212.27\ g/mol)`

`Moles= 0.01413\ mol`

`K_3PO_4` will form ions as:-

`K_3PO_4\rightarrow 3K^++PO_4^(3-)`

Total number of ions = 3 + 1 = 4

Total moles =
`4* 0.01413\ mol=0.05652\ mol`

Volume = 350 mL = 0.35 L ( 1 mL = 0.001 L )

`Molarity=(Moles\ of\ solute)/(Volume\ of\ the\ solution)`

`Molarity=(0.05652)/(0.35)\ M=0.162\ M`

Total concentration of the ions - A) 0.162 M