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Day 14: JEE Mains Chemistry

5 questions. Try each one first, then open its answer.

  1. Question 1

    Chemical Bonding and Molecular Structure. This type asked 6 times: 2021 Paper 19, 25 Jun 2022, 12 Apr 2023, 13 Apr 2023, 24 Jan 2026 S2, 2 Apr 2026 S1. This one: 2 Apr 2026 S1 See all 6 of this type

    28
    Given below are two statements : Statement (I) : The correct sequence of bond lengths in the following species is :
    O2+<O2<O2−<O22−O_{2}^{+} < O_{2} < O_{2}^{-} < O_{2}^{2 -}
    Statement (II) : The correct sequence of number of unpaired electrons in the following species is :
    O2>O2+>O2−>O22−O_{2} > O_{2}^{+} > O_{2}^{-} > O_{2}^{2 -}
    In the light of the above statements, choose the correct answer from the options given below :

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  2. Question 2

    Solutions. This type asked 6 times: 26 Jun 2022, 29 Jun 2022, 25 Jul 2022, 11 Apr 2023, 8 Apr 2024, 2 Apr 2026 S1. This one: 2 Apr 2026 S1 See all 6 of this type

    30
    19.5 g of fluoro acetic acid (molar mass =78 g mol−1= 78\text{ }g{\text{ }mol}^{- 1} ) is dissolved in 500 g of water at 298 K . The depression in the freezing point of water was 1∘C1^{\circ}C. What is KaK_{a} of fluoro acetic acid ? (For water, Kf=1.86 K kg mol−1K_{f}= 1.86\text{ }K\text{ }kg{\text{ }mol}^{- 1} ). Assume molarity and molality to have same values.

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  3. Question 3

    Structure of Atom. This type asked 6 times: 2021 Paper 11, 10 Apr 2023, 13 Apr 2023, 22 Jan 2026 S1, 23 Jan 2026 S1, 2 Apr 2026 S1. This one: 2 Apr 2026 S1 See all 6 of this type

    27
    What is the energy (in J atom−1\mathrm{J\ atom^{-1}}) required for the following process? Li2+(g)→Li3+(g)+e−Li^{2 +}(g) \rightarrow Li^{3 +}(g) +e^{-} (Take the ionization energy for the H atom in the ground state as 2.18×10−18 J atom−12.18 \times10^{- 18}\ \mathrm{J\ atom^{-1}})

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  4. Question 4

    The d- and f-Block Elements. This type asked 6 times: 24 Jan 2023, 25 Jan 2023, 28 Jan 2025, 23 Jan 2026 S2, 24 Jan 2026 S1, 2 Apr 2026 S1. This one: 2 Apr 2026 S1 See all 6 of this type

    36
    Which of the following sets includes all the species that will change the orange colour of K2Cr2O7K_{2}Cr_{2}O_{7} in acidic medium?

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  5. Question 5

    Equilibrium. This type asked 6 times: 28 Jun 2022, 26 Jul 2022, 24 Jan 2023, 30 Jan 2024, 22 Jan 2026 S2, 28 Jan 2026 S1. This one: 28 Jan 2026 S1 See all 6 of this type

    31
    Consider a weak base ' B ' of pKb=5.699pK_{b}= 5.699. ' x ' mL of 0.02 M HCl and ' y ' mL of 0.02 M weak base ' B ' are mixed to make 100 mL of a buffer of pH 9 at 25∘C25^{\circ}C. The values of ' xx ' and ' yy ' respectively are: [Given: log⁡2=0.3010,log⁡3=0.4771,log⁡5=0.699\log2 = 0.3010,\log3 = 0.4771,\log5 = 0.699 ]

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