I'm preparing for a chemistry olympiad.
I'm stuck at this exercise:
2 g of a mixture, made up of barium hydroxide, potassium hydroxide and sodium chloride, was mixed with 0,1 liter, 0,1 mol/l sulfuric acid solution. White precipitate was formed. This precipitate was separated by filtering and drying. The mass of the dry precipitate 0,45 g. To neutralize the filtrate 0,0113 l of 0,2 mol/l sodium hydroxide solution was required.
a) write the equations for all the reactions.
b) count the mass of every substance in the original mixture.
c) count, how many percent of the original mixture were: i) barium ions; ii) potassium ions; iii) sodium ions.
a) 1) Ba(OH)2
(aq) + H2
(s) + 2H2
2) 2KOH(aq) + H2
(aq) + 2H2
3) 2NaCl(aq) + H2
(aq) + HCl(??) question here: in this (3) reaction HCl gas or aq? If aq then it wouldn't be happening, would it?
4) HCl(aq) + NaOH(aq)
NaCl(aq) + H2
b) 1) n(BaSO4
) = 0,45 g/233 g/mol = 0,00193 mol
) = n(Ba(OH)2
) = 0,00193 mol
) = 0,00193 mol x 171 g/mol = 0,33 g.
2) c(NaOH) = 0,2 l/mol = n/0,0113 l => n(NaOH) = 0,2 l/mol x 0,0113 l = 0,00226 mol
I stop here.
What do I do next?
How do I find the mass of potassium sulfate?