Answer: LiF has very high lattice energy; the hydration enthalpy does not overcome it.
- A LiF has very high lattice energy; the hydration enthalpy does not overcome it
- B LiF is a mainly covalent compound that resists hydration largely in most textbook accounts
- C LiCl carries a noticeably higher degree of bond polarity than LiF during normal conditions
- D LiF exists as a volatile gas under standard room conditions as generally observed
Correct answer: A. LiF has very high lattice energy; the hydration enthalpy does not overcome it
Explanation: LiF: high lattice energy (due to small F-) outweighs hydration energy, so it is sparingly soluble. LiCl has lower lattice energy and dissolves readily.
Each s-block metal ion emits a characteristic flame colour because heating excites electrons to higher energy levels; light is emitted as they fall back, with the colour determined by the specific energy gap.
Concept context
Group 1 (alkali metals) and Group 2 (alkaline earth metals). Learn their reactions with water and air, important compounds like NaOH, Na₂CO₃, and CaCO₃, and anomalous behaviour of lithium and beryllium.