What is the concentration of all ions present in .300 mole of sodium phosphate in 600.0 mL of solution?

Question

Luna Chen · Accepted Answer

#["Na"^(+)] = "1.50 mol L"^(-1)#

#["PO"_4^(3-)] = "0.500 mol L"^(-1)# This problem aims to assess your knowledge of the reactions that occur when soluble ionic compounds dissolve in water. Sodium phosphate, #"Na"_3"PO"_4#, is indeed soluble in aqueous solution, which means that its constituent ions, the sodium cation, #"Na"^(+)#, and the phosphate anion, #"PO"_4^(3-)#, will dissociate completely. You'll possess #"Na"_ color(blue)(3) "PO"_ (4(aq)) -> color(blue)(3)"Na"_ ((aq))^(+) + "PO"_ (4(aq))^(3-)# Observe that when sodium phosphate dissolves in a solution, each mole produces In your case, #0.300# moles of sodium phosphate will produce #0.300 color(red)(cancel(color(black)("moles Na"_3"PO"_4))) * (color(blue)(3)color(white)(a)"moles Na"^(+))/(1color(red)(cancel(color(black)("mole Na"_3"PO"_4)))) = "0.900 moles Na"^(+)# and #0.300 color(red)(cancel(color(black)("moles Na"_3"PO"_4))) * "1 mole PO"_4^(3-)/(1color(red)(cancel(color(black)("mole Na"_3"PO"_4)))) = "0.300 moles PO"_4^(3-)# Use the volume of the solution to determine the ion concentration, but first convert it to liters. You will have #["Na"^(+)] = "0.900 moles"/(600.0 * 10^(-3)"L") = color(green)(|bar(ul(color(white)(a/a)color(black)("1.50 mol L"^(-1))color(white)(a/a)|)))# #["PO"_4^(3-)] = "0.300 moles"/(600.0 * 10^(-3)"L") = color(green)(|bar(ul(color(white)(a/a)color(black)("0.500 mol L"^(-1))color(white)(a/a)|)))# Three sig figs are used to round the answers. SIDE NOTE It's worth mentioning that the phosphate anion acts as a base in aqueous solution. The anion accepts a proton from water to form hydrogen phosphate, #"HPO"_4^(2-)#. This means that the concentration of the phosphate anions will actually by slightly smaller than #"0.500 mol L"^(-1)#, since some of the anions will be protonated. The precise concentration of phosphate anions, however, is outside the purview of your inquiry.

Xavier Avery · Answer

undefined To find the concentration of all ions present in 0.300 moles of sodium phosphate in 600.0 mL of solution, you first need to determine the molarity of the sodium phosphate solution. Then, since sodium phosphate dissociates into three ions (Na⁺, PO₄³⁻), you can use stoichiometry to find the concentration of each ion in the solution.