Question

can O3, AsH3 and H2Se act as a lewis acid? please explain.

Answer 1

If O3, As, and Se can accept a pair of electrons, yes. Look at the electronic structure to determine.

Answer 2

Ok ..how do I know if they can or cannot accept an electron pair? Are these exception to the octet rule?Can you show sturture and explaination.

Answer 3

I can't draw structures on this board. Here is an example of a 3d transition element; i.e., say Fe. The electron configuration is
1s2 2s2 2p6 3s2 3p6 3d6 4s2 so the Fe^2+ is
1s2 2s2 2p6 3s2 3p6 3d6 and that gives you 2 3d orbitals (if the 6 that are there pair up) the 4s and the 4p for an octahedral complex of d2sp3 configuration. Since these are electrons donated from some other atom/ion, then Fe^2+ has accepted electrons and that makes it a Lewis acid. Look up the Se and As metals at www.webelements.com for some insight to what they might do. I found the Lewis electron dot structure at the link below. You may want to take a look at that to help determine if any of the three O atoms has extra orbitals which could accept a pair of electrons from another element/ion.
http://www.mikeblaber.org/oldwine/chm1045/notes/Bonding/Resonan/Bond07.htm

Answer 4

Well, My mom use to say
"stupid is , stupid does".. I m getting there. Perhaps, this will help..say, you have O3, AsH3 , H2Se, how would you about explaining whether each of these acts like a Lewis acid, Lewis base or either.? Draing the lewis dot seems to imply that they all have a pair of electrons around the central atom , so they can donate a pair of electrons acting as a lewis base. Am I correct. or not. NOw, the big question.. Can any of them act as a lewis acid..if so, why?
Hopefully, I will understand your answer.

Answer 5

I don't think so. Drawing the Lewis structure DOES show that they have a pair of electronic but to be a Lewis acid the molecule under question (O3, H2Se, AsH3) must accept a pair of electrons so the O3, AsH3, and H2Se are not donating anything. You want to know if they have s, p, d orbitals in their outer shells to ACCEPT electrons. As in the Fe^2+ example I gave above.