Ionic hydrides are compounds formed by metals (usually alkali or alkaline earth metals) with hydrogen, where hydrogen exists as the hydride ion (H⁻).
Properties of ionic hydrides include:
Volatility is generally not applicable to ionic hydrides because they tend to have high melting points and do not easily evaporate. Thus, option (D) is the correct answer.
Ionic hydrides typically have high melting points and are non-volatile because they have ionic bonds between the metal and hydrogen. Ionic compounds generally don't evaporate easily at room temperature, hence they are non-volatile. They also conduct electricity in molten or dissolved states.