I'm retaking my chemistry exam next friday. And I'm still having trouble solving a question from the previous exam.
I've translated it, so some things might not sound quite right. If anything is unclear, feel free to ask and I'll try to explain it a bit better.
On with the question:
A laboratory assitant gets the assignment to prepare Cl2.
Experiment1: To a 300ml solvent of potassium dichromate (0.15 mol) and chrome(III)nitrate (0.015 mol) with pH = 0 (acidulated by addition of nitric acid), 0.03 mol of salt(NaCl) is added.
Experiment2: To a 300ml solvent of potassium dichromate (0.15 mol) and chrome(III)nitrate (0.015 mol) with pH = 0 (acidulated by addition of nitric acid), 2.4 mol of salt(NaCl) is added.
E0=dichromate/chrome(III) = 1.33V
E0=Chloridegas(Cl2; 1atm)/salt = 1.36V
a) Work out the upper reaction completely. (oxidation state, oxidation, reduction, oxidizing agent, reducing agent, work out partial reactions)
b) Calculate the Equilibrium constant of the reaction.
c) Give the schematic representation of the matching galvanic cell and explain.
d) Explain if the goal is reached in both experiments using calculations.
Any help is welcome.. I'm mostly puzzled by the first question. But feel free to answer any of the others aswell.
What I've come up with so far is:
Oxidation - Cr2O72- + 14H+ + 12e- <--> 2Cr + 7H2O
Reduction - Cl2 + 2Na++2e- <--> 2NaCl
Total reaction - K2Cr2O7 + Cr(NO3)3 + HNO3 + 4NaCl + 3H2O <--> 2KCrO4 + 3H+ + Cr(OH)3 + 4NaNO3 + 2Cl2
I have no clue if any of this is right though. The oxidation/reduction aren't even included in the total reaction, so I'm assuming either of them, if not both, are wrong.
Also, sorry if this is in the wrong section. I didn't really know where to put it. Since the course is named general and inorganic chemistry I placed it here.
Thanks in advance for any replies!