The reaction of toluene with Cl₂ in presence of FeCl₃ gives predominantly

Which of the following hydrogen bonds is the strongest?

In which of the following ionization processes, the bond order has increased and the magnetic behaviour has changed?

The charge/size ratio of a cation determines its polarizing power. Which one of the following sequences represents the increasing order of the polarizinig order of the polarizing power of the cationic species, K⁺, Ca²⁺, Mg²⁺, Be²⁺?