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Saturday, 31 October

JEE Main 2021 · ChemistryMultiple choiceAssertion–reasonMediumConceptual

JEE Main 26 February 2021, Shift 2, Chemistry Q38

Question 38 of 90 in this shift, Chemistry question 8 of 30, Section A.

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R. Assertion A : In TlI3\mathrm{TlI_3}, isomorphous to CsI3\mathrm{CsI_3}, the metal is present in +1+1 oxidation state. Reason R : Tl metal has fourteen ff electrons in its electronic configuration. In the light of the above statements, choose the most appropriate answer from the options given below :
  1. (1)Both A and R are correct and R is the correct explanation of A
  2. (2)Both A and R are correct but R is NOT the correct explanation of AOfficial answer
  3. (3)A is correct but R is not correct
  4. (4)A is not correct but R is correct

Official answer

Option 2

NTA final key.

Chapter
The p-Block Elements
Topic
Group 13 & 14
Idea tested
Inert Pair Effect

Same idea in other shifts

Asked 7× in all
  1. 4 Apr 2026, Shift 2 · Q58The electronegativity of a group 13 element 'E' is same as that of Ge (on Pauling scale and upto one decimal point). The CORRECT…HardOther
  2. 7 Apr 2025, Shift 1 · Q60The group 14 elements A and B have the first ionisation enthalpy values of 708 and 715 kJ mol−1\mathrm{mol^{-1}} respectively. The above…MediumSingle correct
  3. 7 Apr 2025, Shift 2 · Q60The correct statements from the following are : (A) Tl3+\mathrm{Tl^{3+}} is a powerful oxidising agent (B) Al3+\mathrm{Al^{3+}} does not get…MediumOther
  4. 6 Apr 2024, Shift 2 · Q67The number of ions from the following that are expected to behave as oxidising agent is :…MediumOther
  5. 8 Apr 2024, Shift 1 · Q66Give below are two statements: One is labelled as Assertion A and the other is labelled as Reason R: Assertion A: The stability order of…EasyAssertion–reason
  6. 26 Jun 2022, Shift 1 · Q66Choose the correct stability order of group 13 elements in their +1 oxidation state.EasySingle 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.