There are some deposits of nitrates and phosphates in the earth's crust. Nitrates are more soluble in water. Nitrates are difficult to reduce under laboratory conditions, but microbes do it easily. Ammonia, forms a large number of complexes with transition metals. Hybridization easily explains the ease of sigma donation capability of \(NH_3\) and \(PH_3\).

Phosphine is an inflammable gas, it is prepared from white phosphorus.

\(NH_3\) is a stronger base than \(PH_3\)

Nitrogen is smaller in size than phosphorus

The correct answer is (2) Nitrogen is smaller in size than phosphorus.

The basicity of a molecule is often related to the availability of a lone pair of electrons. In the case of \(NH_3\) (ammonia) and \(PH_3\) (phosphine), both molecules have a lone pair of electrons on the central atom (nitrogen in \(NH_3\) and phosphorus in \(PH_3\)).

1. Nitrogen is smaller in size than phosphorus:
This statement is correct. Nitrogen has a smaller atomic size compared to phosphorus in the same period of the periodic table.
The smaller size of nitrogen results in a higher electron density on the lone pair of electrons in \(NH_3\).

2. Implication for Basicity:
Smaller atoms tend to have higher electronegativity and higher electron density on lone pairs, making them better electron donors.
\(NH_3\) is a stronger base than \(PH_3\) because the lone pair on nitrogen is more readily available for donation compared to the lone pair on phosphorus in \(PH_3\).

3. Other Statements:
\(PH_3\) does indeed have a lone pair of electrons.
\(NH_3\) also has a lone pair of electrons.

Conclusion:
The correct reason why \(NH_3\) is a stronger base than \(PH_3\) is that nitrogen is smaller in size compared to phosphorus, leading to higher electron density on the lone pair of electrons in \(NH_3\).