The pi bond EXCEPT: I. formed by unhybridized p orbitals II. stronger than sigma bond III. present in double bonds

The pi bond EXCEPT: I. formed by unhybridized p orbitals II. stronger than sigma bond III. present in double bonds

• A. I only
• B. II only
• C. I and II
• D. I and III

Answer: (B)

Pi bonds arise from sideways overlap of unhybridized p orbitals on adjacent atoms. This sideways overlap creates electron density above and below the bond axis, which is less effective than the end-to-end overlap that forms a sigma bond, so pi bonds are weaker and easier to break. In a double bond you indeed have one sigma bond plus one pi bond, so a pi bond is present there. The statement claiming that a pi bond is stronger than a sigma bond is not true; that part is the exception. Therefore, the correct choice is the one that identifies only that false claim.

Pi bonds arise from sideways overlap of unhybridized p orbitals on adjacent atoms. This sideways overlap creates electron density above and below the bond axis, which is less effective than the end-to-end overlap that forms a sigma bond, so pi bonds are weaker and easier to break. In a double bond you indeed have one sigma bond plus one pi bond, so a pi bond is present there. The statement claiming that a pi bond is stronger than a sigma bond is not true; that part is the exception. Therefore, the correct choice is the one that identifies only that false claim.