The correct order of H — M — H bonds angle is : — Chemical Bonding Chemistry Question

💡 Solution & Explanation

Step 1: Analyze the bond angles of Group 15 hydrides (NH3, PH3, AsH3, SbH3, BiH3). Step 2: As we go down the group, the electronegativity of the central atom decreases, causing the bonding pairs to lie further from the central atom and experience weaker repulsions. Alternatively, the involvement of s-character in hybridization decreases (approaching pure p-orbital bonding / Drago's rule), causing the bond angle to drop from ~107° in NH3 to ~90° down the group. Step 3: The decreasing order of bond angle is NH3 > PH3 > AsH3 > SbH3 > BiH3, which means the correct increasing order of bond angle is BiH3 < SbH3 < AsH3 < PH3, corresponding to option (d).