Question

Which of the following is true for allotropes of phosphorus?

• A. Yellow phosphorus is soluble in $C{S}_2$ while red phosphorus is not.
• B. P---P---P bond angle is ${60}^{\circ }$ in red phosphorus.
• C. On heating in air, white phosphorus changes to red.
• D. White phosphorus with slowly change to red phosphorus at ordinary temperatures.

Answer 1

Answer: (A), (D)

The correct options are
A Yellow phosphorus is soluble in $C{S}_2$ while red phosphorus is not.
D White phosphorus with slowly change to red phosphorus at ordinary temperatures.

Structure of red phosphorus is regarded as a polymer consisting of chains of $P_4$ tetrahedral linked together by covalent bond.

On heating in air, white phosphorus changes to black P.

Yellow phosphorus is soluble in $C{S}_2$ while red phosphorus is not.

P---P---P bond angle is ${109}^{\circ }$ in red phosphorus.

Red phosphorus is formed by heating yellow phosphorus, between 240-250${}^{o}C$, in presence of an inert gas.