Answer:
Co⁺² = 0.167 M
Ni⁺² = 0.117 M
Cl⁻ = 0.567 M
Step-by-step explanation:
When the solutions are mixed, the Ni and Co will change between them, so the only salts that can be produced are CoCl₂ and NiCl₂, which are the initial ones. The question already said that they are in aqueous solution, so we can conclude that they are soluble, and after the mixing, there'll be no precipitated formed.
The dissolution happens by the equations below:
CoCl₂ → Co⁺² + 2Cl⁻
NiCl₂ → Ni⁺² + 2Cl⁻
By the stoichiometry of the reactions, the initial molarity of the ions are:
CoCl₂: Co⁺² = 0.250 M, Cl⁻ = 2*0.250 = 0.500 M
NiCl₂: Ni⁺² = 0.350 M, Cl⁻ = 2*0.350 = 0.700 M
The number of moles is the molarity multiplied by the volume in L (0.05 L, and 0.025 L):
nCo⁺² = 0.250*0.05 = 0.0125 mol
nNi⁺² = 0.350*0.025 = 0.00875 mol
nCl⁻ = (0.500*0.05) + (0.700*0.025) = 0.0425 mol
After the mixing, the volume will be 75 mL = 0.075 L, so the concentration will be the number of moles divided by the volume:
Co⁺² = 0.0125/0.075 = 0.167 M
Ni⁺² = 0.00875/0.075 = 0.117 M
Cl⁻ = 0.0425/0.075 = 0.567 M