The number of electron-deficient molecules in which the central atom is sp ^2 hybridized among the following is: BF ₃, BCl ₃, B ₂ H ₆, BeCl ₂( g ), C ₂ H ₄, SO ₂, NH ₃, COCl ₂

Step-by-step solution

First, identify the electron-deficient molecules from the given list. Electron-deficient molecules have a central atom with an incomplete octet or lack sufficient electrons for standard 2c-2e bonds. These are BF ₃ , BCl ₃ , B ₂ H ₆ , and BeCl ₂( g ) . Next, determine the hybridization of the central atom for these four molecules: BF ₃ : Boron has 3 bond pairs and 0 lone pairs sp ^2 hybridized. BCl ₃ : Boron has 3 bond pairs and 0 lone pairs sp ^2 hybridized. B ₂ H ₆ : Each boron atom forms 4 bonds (two terminal, tw