Concept:Hydrogen forms an ionic compound when it exists as the hydride ion,
H−, after gaining an electron from a metal.
Explanation:In
NaH, sodium is a highly electropositive metal.
Sodium transfers its valence electron to hydrogen.
This produces
Na+ and
H− ions.
The strong electrostatic attraction between these oppositely charged ions creates an ionic bond.
In
HCl,
NH3, and
CH4, hydrogen shares electrons with non-metals, forming covalent bonds.
Therefore, only
NaH contains hydrogen in an ionic compound.
Answer:B.
NaH