Potassium is lighter than sodium (Refer table 5.3)
The correct order of density is Li < K < Na < Rb < Cs0.54 < 0.86 < 0.97< 1.53< 1.90(in g cm–3)
Li+ has maximum degree of hydration among alkali metal cations.
Li+ > Na+ > K+ > Rb+ > Cs+
Potassium carbonate cannot be prepared by solvay process. Potassium bicarbonate is fairly soluble in water and does not precipitate out.
ionic character (difference in electronegativity)
MI < MBr < MCl < MF
NaOH ↔ Na+ + OH–
Cathode : Na+ + e– → Na
Anode : 2OH– → H2O + 1/2O2 + 2e–