Alkali Metals Halides - Practice Questions & MCQ

Alkali metals react with halogens to form metal halides, which are ionic in nature.

The reactivity order of alkali metals towards halogens is:

Ionic nature, solubility in H₂O increases while lattice energy decreases.
For example:

These halides are colourless, however, on heating, they become coloured due to nonstoichiometry and crystal defects.

NOTE: 

• LiF is ionic but insoluble in H₂O due to very high lattice energy while LiCl, LiBr, LiI are covalent and hence are less soluble or insoluble as their hydration energy is less than lattice energy.
• Other MX are crystalline solids with high melting and boiling points.
• Halides of K, Rb, Cs can also form polyhalides. For example: