Careers360 Logo
JEE Main Form Correction 2024 Session 2 (Closed) - Last Date, Procedure, Guidelines, Fee

Alkali Metals Halides - Practice Questions & MCQ

Edited By admin | Updated on Sep 18, 2023 18:35 AM | #JEE Main

Quick Facts

  • Halides of Alkali Metals is considered one of the most asked concept.

  • 14 Questions around this concept.

Solve by difficulty

The negative enthalpy of formation for a sodium halide is based on the following trend:

Why lower halides of alkali metals have the same geometry like NaCl?

KBr reacts with ICl to form an ionic solid. What is the solid?

Concepts Covered - 0

Halides of Alkali Metals

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

2 \mathrm{M}+\mathrm{X}_{2}\: \rightarrow \: \mathrm{MX}+\mathrm{Heat}

The reactivity order of alkali metals towards halogens is:

\mathrm{Cs}>\mathrm{Rb}>\mathrm{K}>\mathrm{Na}>\mathrm{Li}

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

\mathrm{LiF}<\mathrm{NaF}<\mathrm{KF}<\mathrm{RbF}<\mathrm{CsF}

\mathrm{KF}<\mathrm{KCl}<\mathrm{KBr}<\mathrm{KI}

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:
    \mathrm{KI}+\mathrm{I}_{2} \longrightarrow \mathrm{KI}_{3}

"Stay in the loop. Receive exam news, study resources, and expert advice!"

Get Answer to all your questions

Back to top