Question

# Which statement about the ammonium ion,$N{{H}_{4}}^{+}$ is correct?(A)All bond angles are ${{107}^{\circ }}$(B)Ammonium ions are formed when ammonia behaves as an acid(C)Ammonium ions are unreactive when heated with NaOH(aq)(D)The bonds are all the same length

Considering option (A) , all bond angles are ${{107}^{\circ }}$. This statement is not correct because the ammonium ion has four bond pairs, which makes the shape of the molecule tetrahedral, and tetrahedral molecules have a bond angle of ${{109.5}^{\circ }}$. There is no lone pair on nitrogen left, to decrease the bond angle of the bond pair. The bond angle of ammonium ion is ${{109.5}^{\circ }}$.
$N{{H}^{+}}+O{{H}^{-}}\to N{{H}_{3}}+{{H}_{2}}O$
Considering option (D), The bonds are all the same length. This statement is correct because all the bonds are $s{{p}^{3}}$hybridized.