Find the correct statements related to…

Single correct+4 / -1Answer matches NTA’s final key

Find the correct statements related to group 15 hydrides.

A. Reducing nature increases from NH $_3$ to BiH $_3$

B. Tendency to donate lone pair of electrons decreases from NH $_3$ to BiH $_3$

C. The stability of hydrides decreases from NH $_3$ to BiH $_3$

D. HEH bond angle decreases from NH $_3$ to SbH $_3$ (E = Elements of group 15)

Choose the correct answer from the options given below:

Solution

Going down the group the central atom grows larger and the E–H bond weaker.

A, true. Weaker E–H bonds give up hydrogen more easily, so reducing power rises to BiH $_3$ .
B, true. The lone pair sits in a larger, more diffuse orbital, so basicity (lone-pair donation) falls.
C, true. Thermal stability falls with the falling E–H bond energy.
D, true. NH $_3$ 107.8°, PH $_3$ 93.6°, AsH $_3$ 91.8°, SbH $_3$ 91.3°: as the central atom gets larger and less electronegative, the bonding pairs sit farther from it and repel each other less, so the angle closes towards the 90° of pure p orbitals.

Answer: A, B, C and D.

Answer checked against the official answer key. The solution is our own working.