See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

Concept: AlCl3 is a Lewis acid (electron-pair acceptor) because aluminum has an incomplete octet with only 6 electrons in its valence shell. CH3OCH3 (dimethyl ether) is a Lewis base (electron-pair donor) because the oxygen atom has lone pairs available for donation. Step 1: Identify the Lewis acid-base interaction. AlCl3 acts as the Lewis acid (electron-pair acceptor) and CH3OCH3 acts as the Lewis base (electron-pair donor) through the oxygen lone pair. Step 2: Determine the direction of electron pair donation. The oxygen in CH3OCH3 donates a lone pair to the empty p-orbital of Al in AlCl3, forming a coordinate (dative) bond from O to Al. Step 3: Assign formal charges. When O donates its lone pair to Al, oxygen loses electron density and gains a formal positive charge (+), while Al receives the electron pair and gains a formal negative charge (-). This results in Al having 4 bonds (3 Cl + 1 O) giving it a negative formal charge, and O having 3 bonds (2 CH3 + 1 Al) giving it a positive formal charge. Step 4: Draw the product. The product is Cl3Al(-)-O(+)(CH3)2, where Al carries a negative formal charge and O carries a positive formal charge, consistent with option (a). Why other options fail: - Option (b): Shows Al with positive charge and O with negative charge — this is the reverse of what actually occurs; O donates electrons TO Al, so Al becomes electron-rich (negative) and O becomes electron-deficient (positive). - Option (c): Shows both Al and O with positive charges — charge balance is violated and mechanistically incorrect. - Option (d): Shows the ether attached to Al without proper bond formation and incorrect charge assignment. Therefore, the correct answer is A.