1. For question 1, we have 4 wells that contained about 2ml of a solution that c
ID: 810192 • Letter: 1
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1. For question 1, we have 4 wells that contained about 2ml of a solution that contained 5 crystals of cobalt II chloride, and 10ml of ethanol which turned the solution blue. Then we added 2 drops of deoinized water into 3 wells and all of them turned pink. So now I need help answering the first question with this information.
2. For this question(step 6), we then took the well to the fume hood and added 5 drops of 12 M Hyrdrochloric acid to well number one. So now well one has 5 drops Hyrdrochloric acid, about 2ml of ethanol with cobalt II chloride. The solution ended up turning turqouis blue. Now For step 7, we then added 2 solid lumps of solid calcium chloride to well 2 and the solution turned dark blue. Given all this information I need help answering the questions, thank you!
1. For question 1, we have 4 wells that contained about 2ml of a solution that contained 5 crystals of cobalt II chloride, and 10ml of ethanol which turned the solution blue. Then we added 2 drops of deoinized water into 3 wells and all of them turned pink. So now I need help answering the first question with this information. 2. For this question(step 6), we then took the well to the fume hood and added 5 drops of 12 M Hyrdrochloric acid to well number one. So now well one has 5 drops Hyrdrochloric acid, about 2ml of ethanol with cobalt II chloride. The solution ended up turning turqouis blue. Now For step 7, we then added 2 solid lumps of solid calcium chloride to well 2 and the solution turned dark blue. Given all this information I need help answering the questions, thank you! 1. Which cobalt complex was favored by the addition of water in Step 5? Use Le Chatelier's Principle to explain the color change. Which cobalt complex was favored in both step 6 and 7? What ion is common to both of the reagents that caused the color change? ? Use Le Chatelier's Principle to explain the color change.Explanation / Answer
[Co(H2O)6]2+ + 4Cl- <=> [CoCl4]- + 6H2O
oct pale pink -> tet bright blue
Although we write it [Co(H2O)6]2+ it is the -ve O atoms of the H2O ligands that bind to the Co2+. The small Co2+ can only have 4 of the larger Cl- ligands in its coordination sphere whereas 6 H2O molecules can fit around it in the aqua cmplx.
Everything remains in soln so solubility is not a factor
The equilibrium lies well over to the left so the solution is in pink color
. It is only at high Cl- conc HCl do you get significant concentration of the [CoCl4]- cmplx ion and the pink soln of [Co(H2O)6]2+ turns blue. The reaction has no significant activation barrier so if we increase the chloride concentration by adding cacl2 intensify the color the blue color. the equilibrium shifts to other direction
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