Solution
Core Logic
(1) Carbon can form pπ - pπ multiple bonds with itself. It is observed in C=C and C ≡ C. (Statement is correct) (2) ECl₃ (E = B and Al): BCl₃ does not form a dimer due to small size of Boron. AlCl₃ forms a dimer Al₂Cl₆ to complete its octet. (Statement is correct) (3) Oxygen exhibits an oxidation state of 0 in O₂, -1 in peroxides (e.g., H₂O₂), -1/2 in superoxides (e.g., KO₂), and +2 in OF₂. Therefore, stating it exhibits only -2 is incorrect. (4) Catenation property of group 14 is highest for Carbon due to strong C-C bonds: C gg Si > Ge ≈ Sn. (Statement is correct)
Step 1: Final Conclusion
Statement (3) is incorrect because Oxygen exhibits multiple oxidation states depending on the compound.
Pattern Recognition
Absolute words like 'only' in oxidation state statements for p-block elements are often false. Oxygen in peroxides, superoxides, and fluorides deviates from the standard -2.
Chapter Mix
Class 11 Chemistry: The p-Block Elements Class 11 Chemistry: Redox Reactions