2 The compound \( \left[\left(\mathrm{CH}_{3}\right)_{3} \mathrm{~N}^{2} \mathrm{AlCl}_{3}\right] \) has a simple molecular structure. Which statement about \( \left(\mathrm{CH}_{3}\right)_{3} \mathrm{NAlCl}_{3} \) is correct? A \( \left(\mathrm{CH}_{3}\right)_{3} \mathrm{NAlCl} l_{3} \) molecules attract each other by hydrogen bonds. B The Al atom has an incomplete valance shell of electrons. C The bonds around the Al atom are planar. D The molecules contain coordinate and covalent bonding

1. The compound is \(\left[\left(\mathrm{CH}_{3}\right)_{3} \mathrm{NAlCl}_{3}\right]\), which can be viewed as the Lewis base \(\left(\mathrm{CH}_{3}\right)_{3}\mathrm{N}\) donating a pair of electrons to the Lewis acid \(\mathrm{AlCl}_{3}\). 2. In the resulting adduct, the bond between the nitrogen of \(\left(\mathrm{CH}_{3}\right)_{3}\mathrm{N}\) and the aluminum of \(\mathrm{AlCl}_{3}\) is formed by a pair of electrons donated by the nitrogen. Although this bond is formed via coordinate (dative) bonding, it is equivalent in many ways to a covalent bond. 3. Thus, the molecule contains both coordinate and covalent bonding. 4. The correct statement is: D. The molecules contain coordinate and covalent bonding.