Answer to Question #90214 in Inorganic Chemistry for Usman

Question #90214

Question:

During electrolysis 0.02 moles moles of metal X is deposited on cathode when 0.12 moles of e- are passed through molten chloride of X. What is the formula of the chloride?

I have tried solving it and my answer is XCl6 which is incorrect. The correct answer given is XCl3. In the explanation the book says that 0.06 moles of e- have flown to cathode and goes on to divide the no. of moles of e- at cathode by no. of moles metal X (0.06/0.02) so it's 3 which means 1 atom of X gains 3 e-'s, giving X +3 charge. What I do not get is what about the other 0.06 mole of e-'s. Isn't metal X supposed to gain all of the 0.12 mole of e-'s ? Shouldn't cathode have the total 0.12 mole of e-'s?

Your answers and explanations will help me a lot, thanks.

Expert's answer

0.12 moles electron passed through molten chloride and cathode and anode. 0.12/2 = 0.06 for cathode.

And 0.06/0.02= 3. giving X +3 charge. Thus XCl3

Now explain why formula xloride cannot be XCl6.

Because metall cannot be VI valence