Question

The properties of ${15}^{th}$ group hydrides which decrease down the group from N to Bi are :

• A. bond angle
• B. reducing power
• C. thermal stability
• D. dipole moment

Answer 1

Answer: (A), (C), (D)

The correct options are
A bond angle
C thermal stability
D dipole moment

Bond angles: $N{H}_3\left({107}^o\right),P{H}_3\left({94}^o\right),As{H}_3\left({92}^o\right),Sb{H}_3\left({91}^o\right)$.
Thermal Stability: $N{H}_3$ is most stable while $Sb{H}_3$ is the least stable.
Dipole moment: Down the group, as the electronegativity of central atom decreases, dipole moment of the hydrides decreases.