Question

Calculate the cadmium ion concentration, [Cd^2+], in a solution prepared by mixing 0.100 L of 0.0100 M Cd(NO₃)₂ with 0.150 L of 0.100 NH₃(aq).

a) 0.0040 M

b) 0.0067 M

c) 0.0100 M

d) 0.0200 M

Answer 1

To find the concentration of [Cd^2+] after mixing, the initial moles of Cd^2+ were calculated and then divided by the new total volume, resulting in a concentration of 0.0040 M, which is answer option a) 0.0040 M.

Step-by-step explanation:

The question asks us to calculate the concentration of cadmium ions, [Cd^2+], after mixing two solutions. Initially, we have 0.100 L of 0.0100 M Cd(NO₃)₂, which gives us a total of (0.100 L) × (0.0100 M) = 0.0010 mol of Cd^2+.

When this is mixed with the ammonia solution, the total volume becomes 0.100 L + 0.150 L = 0.250 L.

As there is no reaction specified between ammonia and cadmium nitrate, and without any given equilibrium constants indicating the formation of complex ions or precipitates, we can assume no reaction takes place, and we only need to account for dilution.

Therefore, the new concentration of Cd^2+ ions is (0.0010 mol) / (0.250 L) = 0.0040 M, which corresponds to option a) 0.0040 M.