Which of the following order is correct ? (1)`SbH_3gtNH_3gtAsH_3gtPH_3`-Boiling point . (2)`NH_3gtPH_3gtAsH_3gtSbH_3`-Thermal stability (3)`NH_4gtPH_3
Which of the following order is correct ?
(1)`SbH_3gtNH_3gtAsH_3gtPH_3`-Boiling point . (2)`NH_3gtPH_3gtAsH_3gtSbH_3`-Thermal stability
(3)`NH_4gtPH_3gtAsH_3gtSbH_3`-Basic character (4)`NH_3gt PH_3gt AsH_3gtSbH_3`-Bond angle
A. (1),(2) and (3) only
B. (2),(3) and (4) only
C. (1),(3) and (4) only
D. (1),(2),(3) and (4)
1 Answers
Correct Answer - D
(1)`NH_3` has higher boiling point than `AsH_3 and PH_3` on account of H-bonding.`SbH_3` has highest boiling point on account of highest molecular weight.
(2)As the size of element increases , the strength of M-H bond decreases and thus stability decreases.
(3)Basic decreases down the group . (Drago rule)
(4)HEH angle `(.^@):NH_3`=107.8, `PH_3=93.6, AsH_3=91.8, SbH_3=91.3`