Calculate x + y + z for H3PO3 acid, where x is no. of lone pairs, y is no. of \sigma bonds and z is — Chemical Bonding Chemistry Question

💡 Solution & Explanation

Step 1: Recognize that CO2, BF3, and CCl4 are highly symmetrical molecules with a net dipole moment of zero (mu = 0). Thus, any polar molecule has a larger dipole moment than these three. Step 2: Compare NH3 and NF3. In NH3, the N-H bond dipoles point toward nitrogen and reinforce the direction of the nitrogen lone pair dipole. In NF3, the highly electronegative fluorine atoms pull electron density away from nitrogen, meaning the N-F bond dipoles oppose the lone pair dipole. Step 3: This partial cancellation in NF3 results in a much smaller net dipole moment than NH3. Thus, NF3's dipole moment is smaller than that of NH3, matching option (a).