Learn

Saturday, 31 October

JEE Main 2020 · ChemistryMultiple choiceDiagram basedMediumApplication

JEE Main 3 September 2020, Shift 2, Chemistry Q45

Question 45 of 75 in this shift, Chemistry question 20 of 25.

The major product in the following reaction is : [figure] →Heatt-BuOH\xrightarrow[\text{Heat}]{\text{t-BuOH}}

The figure, in words

Skeletal line drawings (no atom labels except I, Ot-Bu). Reactant: zigzag line with a vertical line up from the second vertex, a vertical line down from the third vertex, and a vertical line from the fourth vertex up to the label I; the chain ends in a short line down to the right. Option (4) has the same skeleton with the label Ot-Bu in place of I.
  1. (1)[figure: line structure with a double bond at the upper right end of the chain and three other line branches]
  2. (2)[figure: line structure with a double bond between two inner vertices on the right, and line branches]
  3. (3)[figure: line structure with a double bond (drawn doubled) in the middle, two lines going down-left and down-right from its left end, and a line from its right end going up then right]Official answer
  4. (4)[figure: same line skeleton as in the question with Ot-Bu on the line at the upper right vertex in place of I]

Official answer

Option 3

NTA final key (Sep 2020).

Chapter
Haloalkanes and Haloarenes
Topic
SN1 and SN2 Mechanisms
Idea tested
Temperature Effects on Substitution vs Elimination

Same idea in other shifts

Asked 3× in all
  1. 4 Apr 2024, Shift 2 · Q77→ΔKOH(alc)\xrightarrow[\Delta]{\mathrm{KOH(alc)}} major product "P" Product P isMediumDiagram basedHas a figure
  2. 31 Jan 2024, Shift 1 · Q88CH3CH2Br+NaOH\mathrm{CH_3CH_2Br + NaOH} with C2H5OH\mathrm{C_2H_5OH} gives Product A, and with H2O\mathrm{H_2O} gives Product B. The total number of…EasyNumerical valueHas a figure

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. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.