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Saturday, 31 October

JEE Main 2021 · ChemistryMultiple choiceSingle correctMediumRecall

JEE Main 27 August 2021, Shift 2, Chemistry Q36

Question 36 of 90 in this shift, Chemistry question 6 of 30, Section A.

Which one of the following is formed (mainly) when red phosphorus is heated in a sealed tube at 803 K ?
  1. (1)β-Black phosphorus
  2. (2)α-Black phosphorusOfficial answer
  3. (3)White phosphorus
  4. (4)Yellow phosphorus

Official answer

Option 2

NTA final key.

Chapter
The p-Block Elements
Topic
Group 15 & 16
Idea tested
Phosphorus Allotropes

Same idea in other shifts

Asked 2× in all
  1. 30 Jun 2022, Shift 1 · Q70A→573 K\mathrm{A}\xrightarrow{573\ \mathrm{K}} Red phosphorus →under pressureheat ; 803 KB\xrightarrow[\text{under pressure}]{\text{heat ; 803 K}} \mathrm{B} Red…MediumSingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.