Which of the following elements from amphoteric oxides?

Options

A. `N` and `P`
B. `P` and `As`
C. `As` and `Sb`
D. `Sb` and `Bi`

Answer

3

Explanation

Group `15` shows the usual trend, that metallic character increases in decending the group. Thus first two elements `N` and `P`, are nonmetal,`As` and `Sb` are metallodis,Which show metallic as well as nonmetallic properties and `Bi` is a true metal. The increaseing metallic character is shown by the following features.
A. In the appearence and structures of the elements: nitrogen is a colourless gas ,phosphorus is a white, Waxy solid while rest of the elements are brittle ,metallic solids.
B. By their tendency to form positive ions:only antimony and bismuth can from the `3-`valent cation`E^(3+).`
C. By the nature of their oxides: nonmetallic oxides are acidic, metallodic oxides are amphoteric and metallic oxides are typically basic. Thsu the normal oxide of `N` and `P(N_(2)O_(3),P_(4)O_(6))`are stongly acidic, whereas those of `As` and `Sb(As_(4)O_(6), Sb_(4)O_(6))` are amphoteric and that of `Bi(Bi_(2)O_(3))` is largly basic. Antimony (III) oxide, being amphoteric dissolves in sodium hydroxide solution to form an antimontie (III) and in concentrated sulphuric acid to give a sulphate:
`Sb_(4)O_(6)(s)+4OH^(-)(aq. )rarr4SbO_(2)^(-)(aq.)+2H_(2)O(l)`
`Sb_(4)O_(6)(s)+6H_(2)SO_(4)(l)rarr4Sb_(2)(SO_(4))_(3)(a.q)+6H_(2)O(l)`
D.The electrical resistivity of a metallic forms `(alpha-As 33, alpha-Sb 39` and `alpha-Bi 106 mu` ohm cm) are much lower than for white`P(1xx10^(17)mu" ohm cm")`, indicating an increase in metallic properties.
However, the resistivity values are higher than the values for a good conductor such as `Cu, 1.67 mu" ohm cm")` and higher than,`Sn, 11`, and `Pb, 20 mu` ohm cm, in the adjancent group.