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Day 138: JEE Mains Chemistry

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

  1. Question 1

    Amines. Asked once: 27 Jun 2022 (same type asked 4 times) See all 4 of this type

    47
    Given below are two statements: Statements-I: In Hofmann degradation reaction, the migration of only an alkyl group takes place from carbonyl carbon of the amide to the nitrogen atom. Statement-II: The group is migrated in Hofmann degradation reaction to electron deficient atom. In the light of the above statement, choose the most appropriate answer from the options given below:

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  2. Question 2

    Chemical Thermodynamics. Asked once: 5 Apr 2024 (same type asked 4 times) See all 4 of this type

    141
    Combustion of 1 mole of benzene is expressed at C6H6(l)+152O2( g)→6CO2( g)+3H2O(l)C_{6}H_{6}(l) +\frac{15}{2}O_{2}(\text{ }g) \rightarrow 6CO_{2}(\text{ }g) + 3H_{2}O(l). The standard enthalpy of combustion of 2 mol of benzene is - ' xx ' kJ. x=x = _______ . (1) standard Enthalpy of formation of 1 mol1\text{ }mol of C6H6(l)C_{6}H_{6}(l), for the reaction 6C6C (graphite) +3H2( g)→C6H6(l)+ 3H_{2}(\text{ }g) \rightarrow C_{6}H_{6}(l) is 48.5 kJ mol−148.5\text{ }kJ{\text{ }mol}^{- 1}. (2) Standard Enthalpy of formation of 1 mol1\text{ }mol of CO2( g)CO_{2}(\text{ }g), for the reaction CC (graphite) +O2(g)→CO2( g)+O_{2(g)}\rightarrow CO_{2}(\text{ }g) is −393.5 kJ mol−1- 393.5\text{ }kJ{\text{ }mol}^{- 1}. (3) Standard and Enthalpy of formation of 1 mol of H2O(l)H_{2}O(l), for the reaction
    H2( g)+12O2( g)→H2O(l) is −286 kJ mol−1H_{2}(\text{ }g) +\frac{1}{2}O_{2}(\text{ }g) \rightarrow H_{2}O(l)\text{~is~}- 286\text{ }kJ{\text{ }mol}^{- 1}

  3. Question 3

    Classification of Elements and Periodicity. Asked once: 22 Jan 2026 S1 (same type asked 4 times) See all 4 of this type

    30
    A 'p'-block element (E) and hydrogen form a binary cation (EHx)+\left( EH_{x} \right)^{+}, while EH3EH_{3} on treatment with K2HgI4K_{2}HgI_{4} in alkaline medium gives a precipitate of basic mercury(II) amido-iodide. Given below are first ionisation enthalpy values ( kJmol−1kJmol^{- 1} ) for first element each from group 13, 14, 15 and 16. Identify the correct first ionisation enthalpy value for element E .

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  4. Question 4

    Solutions. Asked once: 23 Jan 2026 S1 (same type asked 4 times) See all 4 of this type

    27
    Which one of the following graphs accurately represents the plot of partial pressure of CS2CS_{2} vs its mole fraction in a mixture of acetone and CS2CS_{2} at constant temperature?

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  5. Question 5

    Some Basic Concepts of Chemistry. Asked once: 26 Jul 2022 (same type asked 4 times) See all 4 of this type

    145
    20 mL20\text{ }mL of 0.02M0.02M hypo solution is used for the titration of 10 mL10\text{ }mL of copper sulphate solution, in the presence of excess of KI using starch as an indicator. The molarity of Cu2+Cu^{2 +} is found to be ×10−2M\times10^{- 2}M [nearest integer] Given: 2Cu2++4I−→Cu2I2+I22Cu^{2 +}+ 4I^{-}\rightarrow Cu_{2}I_{2}+I_{2}
    I2+2 S2O3 2−→2I−+S4O6 2−I_{2}+ 2{\text{ }S}_{2}O_{3}\ ^{2 -}\rightarrow 2I^{-}+S_{4}O_{6}\ ^{2 -}