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?

Question

Quizplus · Accepted Answer

To find the total concentration of ions in the solution, we need to first calculate the number of moles of KS1U1B13S1U1B0POS1U1B14S1U1B0 in the solution:

moles of KS1U1B13S1U1B0POS1U1B14S1U1B0 = mass / molar mass
moles of KS1U1B13S1U1B0POS1U1B14S1U1B0 = 3.00 g / 174.27 g/mol = 0.01723 mol

Since KS1U1B13S1U1B0POS1U1B14S1U1B0 is a salt that dissociates in water, it will form K+ and S1U1B0P2O72- ions. The concentration of each ion can be calculated using the number of moles and the volume of the solution:

concentration of K+ = moles of K+ / volume of solution 
concentration of K+ = 0.01723 mol / 0.350 L = 0.0492 M

concentration of S1U1B0P2O72- = moles of S1U1B0P2O72- / volume of solution 
concentration of S1U1B0P2O72- = 0.01723 mol / 0.350 L = 0.0492 M

The total concentration of ions in the solution is the sum of the concentration of K+ and S1U1B0P2O72-:

total concentration of ions = concentration of K+ + concentration of S1U1B0P2O72-
total concentration of ions = 0.0492 M + 0.0492 M = 0.0984 M

However, this calculation ignores the reaction of S1U1B0P2O72- with water, which leads to the formation of HPO42- and OH-. This reaction will decrease the concentration of S1U1B0P2O72- ions and increase the concentration of HPO42- and OH- ions. Since we don't know the extent of this reaction, the best choice is to use the initial concentrations of K+ and S1U1B0P2O72- to estimate the total concentration of ions in the solution. The only option that uses these initial concentrations is B, which gives a total concentration of ions of 0.0984 M, as calculated above.

If the Reaction of Phosphate Ion with Water Is Ignored,what