JEE Main 2022 · ChemistryMultiple choiceSingle correctEasyRecall

JEE Main 29 July 2022, Shift 2, Chemistry Q69

Question 69 of 90 in this shift, Chemistry question 9 of 30, Section A.

When borax is heated with CoO on a platinum loop, blue coloured bead formed is largely due to

(1) $\mathrm{B_2O_3}$
(2) $\mathrm{Co(BO_2)_2}$ Official answer
(3) $\mathrm{CoB_4O_7}$
(4) $\mathrm{Co[B_4O_5(OH)_4]}$

Official answer

Option 2

NTA final key.

Chapter: The p-Block Elements
Topic: Group 13 & 14
Idea tested: Borax Bead Test Chemistry

Same topic in other shifts

All Group 13 & 14 questions

2 Apr 2026, Shift 2 · Q70Among Fe $^{2+}$ , Fe $^{3+}$ , Cr $^{2+}$ and Zn $^{2+}$ , the ion that shows positive borax bead test and with highest ionisation enthalpy is:MediumSingle correct
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
6 Apr 2026, Shift 1 · Q59Given below are two statements: Statement I: Aluminium is more electropositive than thallium as the standard electrode potential value of…MediumTwo statements
3 Apr 2025, Shift 2 · Q60The correct orders among the following are A. Atomic radius : B < Al < Ga < In < Tl B. Electronegativity : Al < Ga < In < Tl < B C.…MediumOther
4 Apr 2025, Shift 2 · Q57The elements of Group 13 with highest and lowest first ionisation enthalpies are respectively :EasySingle correct
4 Apr 2025, Shift 2 · Q58Given below are two statements : Statement (I) : The first ionisation enthalpy of group 14 elements is higher than the corresponding…MediumTwo statements

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.