JEE Main 2022 · 30 Jun · Shift 1 · Chemistry Q70

ChemistrySingle correct+4 / -1Question 70 of 90

$\mathrm{A\xrightarrow{573\ K}Red\ phosphorus\xrightarrow[under\ pressure]{heat;\ 803\ K}B}$

Red phosphorus is obtained by heating "A" at 573 K, and can be converted to "B" by heating at 803 K under pressure.

A and B, respectively, are

\beta

-black phosphorus and white phosphorus.

white phosphorus and

\beta

-black phosphorus.

\alpha

-black phosphorus and white phosphorus.

white phosphorus and

\alpha

-black phosphorus.

Answer and worked solution

Official answer: D

Forms. White phosphorus gives red P at 573 K; red P heated at 803 K in a sealed tube gives α-black phosphorus.

(D)

Topics:Group 15

JEE Main 2022 · 30 Jun · Shift 1, Chemistry question 70