Question

Which of the following statements is correct?

• A. some metallic hydrides are non-stoichiometric
• B. Metallic hydrides conduct heat and electricity
• C. Ionic hydrides do not conduct electricity in solid state
• D. Ionic hydrides are very good conductors of electricity in solid state

Answer 1

Answer: (A), (B), (C)

The correct options are
A some metallic hydrides are non-stoichiometric
B Metallic hydrides conduct heat and electricity
C Ionic hydrides do not conduct electricity in solid state

Saline or salt-like hydrides may be thought of containing metallic cations
and the hydride anion $H^{-}$. Molten $LiH$ conducts electricity just like
molten $NaCl$. This is why they are "salt like". Their (ionic hydrides)
crystal structures are known and there is no directional bonding involved.
These hydrides are denser than the parent metal and this may be explained by
visualizing the lattice being made of cations and hydride anions.

Metallic hydrides generally tend to mimic the characteristics of the parent metal.
They are hard, lustrous (metallic) and they conduct electricity. Also they may have
magnetic properties similar to the parent metal. Such hydrides are less dense than the
parent metal. This is because the lattice has expanded to accommodate hydrogen.