Import Question JSON

$\text{NH}_3 \text{ is highly soluble in water but other hydrides are less soluble because } \text{NH}_3 \text{ show hydrogen bonding with water.}$ $\text{Down the group reducing nature increases. This shows that bond strength M-H decreases as the electronegativity of M decreases. } \text{NH}_3 \text{ is a weak reducing agent while } \text{AsH}_3\text{, } \text{SbH}_3 \text{ and } \text{BiH}_3 \text{ are powerful reducing agents.}$ $\text{In } \text{NH}_3\text{, molecules are associated with hydrogen bonding and thus its boiling point is comparatively high in comparison to } \text{PH}_3 \text{ and } \text{AsH}_3 \text{ where no hydrogen bonding is present.}$ $\text{The basic character decreases from } \text{NH}_3 \text{ to } \text{BiH}_3\text{. The basic nature is due to the presence of lone pair of electrons on the central atom. } \text{NH}_3 \text{ is the strongest electron-pair donor due to its small size' as the electron density of the electron pair is concentrated over a small region. As the size increases the electron density gets diffused over a large region and hence the ability to donate the electron pair (basic nature) decreases.}$ $\text{Hence, option 4th is the correct answer.}$