We’re being asked to predict the reaction between AlCl3 and NH3 in a solvent that does not participate as a reactant.
We know that AlCl3 produces the same effect as the addition of H+.
Recall that, in neutralization reactions, adding an H+ is similar to donating a proton → by definition, an acid is a proton donor.
This means that AlCl3 acts like an acid but since it does not have an H+ → we will use the Lewis definition of acids and bases.
Based on the Lewis definition:
Lewis acid is an electron pair acceptor.
Some characteristics of a Lewis acid:
• When hydrogen is connected to an electronegative element such as P, O, N, S or halogens
▪ hydrogen gains a partially positive charge → makes hydrogen act as a Lewis acid
• Positively charged metal ions