Does a reaction occur when aqueous solutions of barium sulfide and cobalt(ii) iodide are combined?

Question

If a reaction occurs write the net ionic equation

Answer 1

Yes a reaction occurs because Cobalt II Sulfide (CoS) is insoluble in water.

The net ionic equation is CO+² (aq) + S^-2 (aq) -----> CoS (s)

Answer 2

Hi Brooke A.,

To find out the answer to your question, look up "Barium Sulfide" on the internet, particularly the purification: It dissolves well in hot water, and quite well in cold water, too. (If it weren't very soluble, then perhaps it wouldn't present with enough concentration to precipitate with Co+2, if Co+2 sulfide was comparably insoluble. Then you would have to do some calculations, wouldn't you.)

Ksp for Co(II)S = 4 x 10^-21 .(Look up "Ksp" on internet.) That should tell you right away, it's insoluble! Very insoluble!

The only other species of interest, BaI₂ , is soluble in water (again, look up its properties on the internet). So you don't have to worry about it dropping out.

-- Cheers, -- Mr. d.