There are some deposits of nitrated 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 metal ions. Hybridisation easily explains the ease of sigma donation capability of `NH_3` and `PH_3`. Phosphine is a flammable gas and is prepared from white phosphorous.
Which of the following statement is correct ?

Options

A. Between `NH_3` and `PH_3, NH_3` is a better electron donar because the lone pair of electrons occupies spherical s-orbital and is less directional.
B. Between `NH_3` and `PH_3, PH_3` is a better electron donar because the lone pair of electrons occupies `sp^3`-orbital and is more directional.
C. Between `NH_3` and `OH_3,NH_3`, is a better electron donar because the lone pair of electrons occupies `sp^3`-orbital and is more directional.
D. Between `NH_3` and `PH_3, PH_3` is a better electron donar because the lone pair of electrons occupies spherical s-orbital and is less directional.

Answer

C

Explanation

Both `NH_3` and `PH_3` are `sp^3` hybridised with pyramidal in shape.
`NH_3` is a better electron donor than phosphine because the lone pair of electrons occupies the `sp^3` -orbital and is more directional. It is easily donatable. Due to small size of `N`, the lone pair electron density is higher in `NH_3`, than in `PH_3`, so `NH_3` is better electron donor.