Why tendency to behave as Lewis acid decreases down the group in boron family
BCl3 and AlCl3 behave as good Lewis acids but down the group,the behaviour changes. To provide a meaningful explanation,we should se why these two are so good lewis acids. See the electron donation into the empty 2p orbital of BCl3 by oxygen.
Similarly Al accepts electrons in 3p empty orbital to show Lewis acidity. But as we go down the group,energy of p orbitals increase and they no longer lie accept electrons in them,since,electrons are donated only in those orbitals that are lower in energy like 2p and 3p.
Similarly Al accepts electrons in 3p empty orbital to show Lewis acidity. But as we go down the group,energy of p orbitals increase and they no longer lie accept electrons in them,since,electrons are donated only in those orbitals that are lower in energy like 2p and 3p.