Question

Which of the following can be classified as a molecular hydride ?

• A. $LiH$
• B. ${NH}_3$
• C. ${NiHO}_6$
• D. ${MgH}_2$

Answer 1

The correct option is B ${NH}_3$

Hydride is the product when hydrogen reacts with any other elements, except the noble gases. So hydrides are compounds where one atom is hydrogen to another more electropositive element. A hydride is an anion of hydrogen $\left(H^{-}\right)$.

Bonding between hydrogen & other elements is always covalent. General chemical formula of a hydride is $M{H}_x$ where $M=$ other element with hydrogen makes a binary compound. $x=$ no. of hydrogen atoms.

Covalent or Molecular hydrides

Hydrogen atoms from a covalent bond with $p-$block atoms. General chemical formula$-X{H}_{(8-n)}$ where $n=$no. of electrons the element has in its atomic shell.

$N{H}_3$ is $c$ molecular hydride

$3H_{2\left(g\right)}+N_{2\left(g\right)}\to 2N{H}_{3\left(g\right)}$

Answer is $B)N{H}_3$