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Saturday, 31 October

JEE Main 2020 · ChemistryMultiple choiceSingle correctMediumApplication

JEE Main 8 January 2020, Shift 1, Chemistry Q39

Question 39 of 75 in this shift, Chemistry question 14 of 25, Section A.

The most suitable reagent for the given conversion is :

The figure, in words

Reaction scheme: a decalin (bicyclic saturated) bearing CONH2, C(=O)CH3, CN and CO2H substituents is converted (reagent '?') into the same decalin with CONH2, COCH3, CN unchanged and CO2H replaced by CH2OH (HOH2C).
  1. (1)LiAlH4\mathrm{LiAlH_4}
  2. (2)B2H6\mathrm{B_2H_6}Official answer
  3. (3)H2/Pd\mathrm{H_2/Pd}
  4. (4)NaBH4\mathrm{NaBH_4}

Official answer

Option 2

NTA final key (Jan 2020).

Chapter
Aldehydes, Ketones and Carboxylic Acids
Topic
Carboxylic Acids and Derivatives
Idea tested
Reduction of Acids

Same idea in other shifts

Asked 5× in all
  1. 1 Feb 2024, Shift 1 · Q76Match List - I with List - II. List - I (Reactions) (A) CH3(CH2)5−C(=O)−OC2H5⟶CH3(CH2)5CHO\mathrm{CH_3(CH_2)_5-C(=O)-OC_2H_5 \longrightarrow CH_3(CH_2)_5CHO} (B)…MediumMatch the list
  2. 8 Apr 2023, Shift 1 · Q74The major product formed in the following reaction is: [reaction: ortho-disubstituted benzene bearing CH2CH2CO2H\mathrm{CH_2CH_2CO_2H} and…MediumDiagram basedHas a figure
  3. 26 Jun 2022, Shift 2 · Q75The reagent, from the following, which converts benzoic acid to benzaldehyde in one step is [drawn benzene ring with COOH, arrow, drawn…MediumSingle correctHas a figure
  4. 26 Aug 2021, Shift 2 · Q45Match List - I with List - II. List - I (Chemical Reaction) (a) CH3COOCH2CH3→CH3CH2OH\mathrm{CH_3COOCH_2CH_3} \rightarrow \mathrm{CH_3CH_2OH} (b)…MediumMatch the listHas 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.