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Day 76: JEE Mains Chemistry

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

  1. Question 1

    Some Basic Concepts of Chemistry. Asked 2 times: 29 Jun 2022*, 24 Jan 2025 (* = numbers or wording changed that year) See all 2 times it was asked

    50
    Consider the following reaction occurring in the blast furnace.
    Fe3O4( s)+4CO(g)→3Fe(l)+4CO2( g)Fe_{3}O_{4(\text{ }s)}+ 4CO_{(g)}\rightarrow 3Fe_{(l)}+ 4CO_{2(\text{ }g)}
    'xx' kg of iron is produced when 2.32×103 kg2.32 \times10^{3}\text{ }kg Fe3O4Fe_{3}O_{4} and 2.8×102 kgCO2.8 \times10^{2}\text{ }kgCO are brought together in the furnace. The value of ' xx ' is ____\_\_\_\_ . (nearest integer) {Given : Molar mass of Fe3O4=232 g mol−1Fe_{3}O_{4}= 232\text{ }g{\text{ }mol}^{- 1} Molar mass of CO=28 g mol−1CO = 28\text{ }g{\text{ }mol}^{- 1} Molar mass of  Fe=56 g mol−1}\left. \ Fe = 56\text{ }g{\text{ }mol}^{- 1} \right\}

  2. Question 2

    Chemical Thermodynamics. Asked 2 times: 2021 Paper 24*, 23 Jan 2025 (* = numbers or wording changed that year) See all 2 times it was asked

    50
    The standard enthalpy and standard entropy of decomposition of N2O4N_{2}O_{4} to NO2NO_{2} are 55.0 kJ mol−155.0\text{ }kJ{\text{ }mol}^{- 1} and 175.0 J/K/mol175.0\text{ }J/K/mol respectively. The standard free energy change for this reaction at 25∘C25^{\circ}C in Jmol−1Jmol^{- 1} is ______\_\_\_\_\_\_ (Nearest integer)

  3. Question 3

    Electrochemistry. Asked 2 times: 10 Apr 2023*, 23 Jan 2025 (* = numbers or wording changed that year) See all 2 times it was asked

    30
    FeO42−→+2.0VFe3+→0.8VFe2+→−0.5VFe0FeO_{4}^{2 -}\overset{+ 2.0V}{\rightarrow}Fe^{3 +}\overset{0.8V}{\rightarrow}Fe^{2 +}\overset{- 0.5V}{\rightarrow}Fe^{0} In the above diagram, the standard electrode potentials are given in volts (over the arrow). The value of EFeO42−/Fe2+⊖E_{FeO_{4}^{2 -}/Fe^{2 +}}^{\ominus} is

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  4. Question 4

    Some Basic Concepts of Chemistry. Asked 2 times: 29 Jan 2023*, 23 Jan 2025 (* = numbers or wording changed that year) See all 2 times it was asked

    121
    0.01 mole of an organic compound (X) containing 10%10\% hydrogen, on complete combustion produced 0.9 gH2O0.9\text{ }gH_{2}O. Molar mass of (X)(X) is ___\_\_\_ gmol−1gmol^{- 1}.

  5. Question 5

    Chemical Thermodynamics. Asked 2 times: 14 Jun 2022*, 22 Jan 2025 (* = numbers or wording changed that year) See all 2 times it was asked

    124
    Consider the following cases of standard enthalpy of reaction (ΔHr∘\left( \Delta H_{r}^{\circ} \right. in  kJmol−1)\left. \ kJmol^{- 1} \right)
    C2H6( g)+72O2( g)→2CO2( g)+3H2O(l)ΔH1∘=−1550C( graphite )+O2( g)→CO2( g)ΔH2∘=−393.5H2( g)+12O2( g)→H2O(l)ΔH3∘=−286\begin{matrix} & C_{2}H_{6}(\text{ }g) +\frac{7}{2}O_{2}(\text{ }g) \rightarrow 2CO_{2}(\text{ }g) + 3H_{2}O(l)\quad \Delta H_{1}^{\circ}= - 1550 \\ & C(\text{~graphite~}) +O_{2}(\text{ }g) \rightarrow CO_{2}(\text{ }g)\quad \Delta H_{2}^{\circ}= - 393.5 \\ & H_{2}(\text{ }g) +\frac{1}{2}O_{2}(\text{ }g) \rightarrow H_{2}O(l)\quad \Delta H_{3}^{\circ}= - 286 \end{matrix}
    The magnitude of ΔfH∘\Delta_{f}H^{\circ} of C2H6(g)C_{2}H_{6}(g) is ______\_\_\_\_\_\_ kJmol−1kJmol^{- 1} (Nearest integer).