Question:hard

Lithium aluminium hydride can be prepared from the reaction of

Updated On: Apr 1, 2026
  • $LiH$ and $Al ( OH )_3$
  • $LiCl$ and $Al _2 H _6$
  • $LiCl , Al$ and $H _2$
  • $LiH$ and $Al _2 Cl _6$
Show Solution

The Correct Option is D

Solution and Explanation

Lithium aluminium hydride (\(LiAlH_4\)) is an important compound used as a reducing agent in organic chemistry. It is prepared through a chemical reaction between lithium hydride and aluminium chloride. The correct reaction is as follows:

The reaction between lithium hydride (\(LiH\)) and aluminium chloride (\(Al_2Cl_6\)) can be written as:

\(6LiH + Al_2Cl_6 \rightarrow 2LiAlH_4 + 4LiCl\)

This reaction shows lithium hydride reacting with aluminium chloride to form lithium aluminium hydride and lithium chloride as a byproduct.

Explanation of Options:

  • $LiH$ and $Al(OH)_3$: This combination does not result in the formation of lithium aluminium hydride as $Al(OH)_3$ is not reactive enough to interact with $LiH$ to form $LiAlH_4$.
  • $LiCl$ and $Al_2H_6$: This pair is incorrect because $Al_2H_6$ (dimer of dihydroaluminium chloride) is not used in such reactions to produce $LiAlH_4$.
  • $LiCl$, $Al$, and $H_2$: This combination does not lead directly to the formation of $LiAlH_4$ and is not a recognized method of preparation for the compound.
  • $LiH$ and $Al_2Cl_6$: Correct option. The reaction between lithium hydride and aluminium chloride forms lithium aluminium hydride, as shown above.

Therefore, the correct answer is the combination of \(LiH\) and \(Al_2Cl_6\) which forms lithium aluminium hydride.

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