Question

Among the following, which one is the strongest base? Give reasons
1. $NH _{3}$
2. $PH _{3}$
3. $AsH _{3}$
4. $SbH _{3}$

Answer 1

The basicity of hydrides increases from bottom to top in a period. Due to increase in size from top to bottom, electron density around the nucleus decreases. This leads to a decrease in basicity from top to bottom.
So NH₃ is the strongest base