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## Thermodynamics

### Chemistry

#### Previous Years Questions

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\begin{aligned} &\mathrm{C}(\mathrm{s})+\mathrm{O}_{2}(\mathrm{~g}) \rightarrow \mathrm{CO}_{2}(\mathrm{~g})+400 \mat... JEE Main 2022 (Online) 29th July Evening Shift Given below are two statements: One is labelled as Assertion\mathbf{A}$$and the other is labelled as Reason$$\mathb...
JEE Main 2022 (Online) 28th July Evening Shift
Which of the following relation is not correct?
JEE Main 2022 (Online) 28th July Morning Shift
For micelle formation, which of the following statements are correct? A. Micelle formation is an exothermic process. B. ...
JEE Main 2022 (Online) 25th July Evening Shift
At 25$$^\circ$$C and 1 atm pressure, the enthalpies of combustion are as given below : .tg {border-collapse:collapse;b...
JEE Main 2022 (Online) 24th June Evening Shift
At 25$$^\circ$$C and 1 atm pressure, the enthalpy of combustion of benzene (I) and acetylene (g) are $$-$$ 3268 kJ mol$$... JEE Main 2022 (Online) 25th June Evening Shift Match List-I with List-II. .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:sol... JEE Main 2022 (Online) 27th June Morning Shift The incorrect expression among the following is : JEE Main 2021 (Online) 31st August Evening Shift During which of the following processes, does entropy decrease?(A) Freezing of water to ice at 0$$^\circ$$C(B) Freezing ... JEE Main 2021 (Online) 17th March Evening Shift For a reaction, 4M(s) + nO2(g)$$ \to $$2M2On(s) the free energy change is plotted as a function of temperature. The te... JEE Main 2020 (Online) 6th September Evening Slot Lattice enthalpy and enthalpy of solution of NaCl are 788 kJ mol–1, and 4 kJ mol–1, respectively. The hydration enthalpy... JEE Main 2020 (Online) 5th September Evening Slot Five moles of an ideal gas at 1 bar and 298 K is expanded into vacuum to double the volume. The work done is : JEE Main 2020 (Online) 4th September Evening Slot The process that is NOT endothermic in nature is : JEE Main 2020 (Online) 4th September Evening Slot For one mole of an ideal gas, which of these statements must be true? (a) U and H each depends only on temperature (b) C... JEE Main 2020 (Online) 4th September Morning Slot The true statement amongst the following is: JEE Main 2020 (Online) 9th January Evening Slot If enthalpy of atomisation for Br2(1) is x kJ/mol and bond enthalpy for Br2 is y kJ/mol, the relation between them :... JEE Main 2020 (Online) 9th January Morning Slot According to the following diagram, A reduces BO2 when the temperature is : ... JEE Main 2020 (Online) 9th January Morning Slot A graph of vapour pressure and temperature for three different liquids X, Y, and Z is shown below : The following infer... JEE Main 2020 (Online) 8th January Morning Slot Indentify the correct labels of A,B and C in the following graph from the options given below : Root mean square speed ... JEE Main 2020 (Online) 7th January Evening Slot The INCORRECT match in the following is : JEE Main 2019 (Online) 12th April Evening Slot An ideal gas is allowed to expand form 1 L to 10 L against a constant external pressure of I bar. The work done in kJ is... JEE Main 2019 (Online) 12th April Morning Slot Enthalpy of sublimation of iodine is 24 cal g–1 at 200 oC. If specific heat of I2(s) and l2 (vap) are 0.055 and 0.031 c... JEE Main 2019 (Online) 12th April Morning Slot The difference between$$\Delta $$H and$$\Delta $$U ($$\Delta $$H –$$\Delta $$U), when the combustion of one mole of h... JEE Main 2019 (Online) 10th April Evening Slot A process will be spontaneous at all temperatures if : JEE Main 2019 (Online) 10th April Morning Slot Consider the given plot of enthalpy of the following reaction between A and B. A+ B$$ \to $$C + D Identify the incorre... JEE Main 2019 (Online) 9th April Evening Slot During compression of a spring the work done is 10kJ and 2kJ escaped to the surroundings as heat. The change in internal... JEE Main 2019 (Online) 9th April Evening Slot Among the following, the set of parameters that represents path function, is : (A) q + w (B) q (C) w (D) H–TS... JEE Main 2019 (Online) 9th April Morning Slot 5 moles of an ideal gas at 100 K are allowed to undergo reversible compression till its temperature becomes 200 K. If CV... JEE Main 2019 (Online) 8th April Evening Slot Which one of the following equations does not correctly represent the first law of thermodynamics for the given processe... JEE Main 2019 (Online) 8th April Morning Slot For silver, Cp(J K–1 mol–1) = 23 +0.01 T. If the temperature (T) of 3 moles of silver is raised from 300 K to 1000 K at ... JEE Main 2019 (Online) 8th April Morning Slot The combination of plots which does not represent isothermal expansion of an ideal gas is – ... JEE Main 2019 (Online) 12th January Evening Slot For diatomic ideal gas in a closed system, which of the following plots does not correctly describe the relation between... JEE Main 2019 (Online) 12th January Morning Slot The standard reaction Gibbs energy for a chemical reaction at an absolute temperature T is given by$$\Delta $$rGo = A –... JEE Main 2019 (Online) 11th January Evening Slot The reaction, MgO(s) + C(s)$$ \to $$Mg(s) + CO(g), for which$$\Delta $$rHo + 491.1 kJ mol–1 and$$\Delta $$rSo = 198.... JEE Main 2019 (Online) 11th January Evening Slot Two blocks of the same metal having same mass and at temperature T1 and T2, respectively, are brought in contact with ea... JEE Main 2019 (Online) 11th January Morning Slot For the chemical reaction X$$\rightleftharpoons$$Y, the standard reaction Gibbs energy depends on temperature T (in ... JEE Main 2019 (Online) 11th January Morning Slot An ideal gas undergoes isothermal compression from 5m3 to 1 m3 against a constant external pressure of 4 Nm–2. Heat rel... JEE Main 2019 (Online) 10th January Evening Slot The process with negative entropy change is JEE Main 2019 (Online) 10th January Evening Slot The values of Kp/Kc for the following reactions at 300 K are, respectively : (At 300 K, RT = 24.62 dm3 atm mol–1) N2(g)... JEE Main 2019 (Online) 10th January Morning Slot A process has$$\Delta $$H = 200 J mol–1 and$$\Delta $$S = 40 JK–1 mol–1. Out of the values given below, choose the min... JEE Main 2019 (Online) 10th January Morning Slot The entropy change associated with the conversion of 1 kg of ice at 273 K to water vapours at 383 K is : (Specific heat... JEE Main 2019 (Online) 9th January Evening Slot Consider the reversible isothermal expansion of an ideal gas in a closed system at two different temperatures T1 and T2 ... JEE Main 2019 (Online) 9th January Morning Slot For which of the following processes,$$\Delta $$S is negative ? JEE Main 2018 (Online) 16th April Morning Slot At 320 K, a gas A2 is 20% dissociated to A(g). The standard free energy change at 320 K and 1 atm in J mol-1 is approxim... JEE Main 2018 (Online) 16th April Morning Slot Given (i)&nbsp;&nbsp; 2Fe2O3(s)$$ \to $$4Fe(s) + 3O2(g);$$\Delta $$rGo = + 1487.0 kJ mol-1 (ii)&nbsp;&nbsp; 2CO(g) +... JEE Main 2018 (Online) 15th April Evening Slot$$\Delta $$fGo at 500 K for substance 'S' in liquid state and gaseous state are +100.7 kcl mol-1 and +103 kcal mol-1, re... JEE Main 2018 (Online) 15th April Evening Slot An ideal gas undergoes a cyclic process as shown in Figure.$$\Delta $$UBC =$$-$$5 kJ mol-1, qAB =$$2$$kJ mol-1, WAB ... JEE Main 2018 (Online) 15th April Morning Slot For which of the following reactions,$$\Delta $$H is equal to$$\Delta $$U? JEE Main 2018 (Online) 15th April Morning Slot Which of the following lines correctly show the temperature dependence of equilibrium constant K, for an exothermic reac... JEE Main 2018 (Offline) The combustion of benzene(l) gives CO2(g) and H2O(l). Given that heat of combustion of benzene at constant volume is –32... JEE Main 2018 (Offline) A gas undergoes change from state A to state B. In this process, the heat absorbed and work done by the gas is 5 J and 8... JEE Main 2017 (Online) 9th April Morning Slot An ideal gas undergoes isothermal expansion at constant pressure. During the process : JEE Main 2017 (Online) 9th April Morning Slot The enthalpy change on freezing of 1 mol of water at 5oC to ice at −5oC is : (Given$$\Delta $$fusH = 6 kJ mol$$-$$1 at ... JEE Main 2017 (Online) 8th April Morning Slot For a reaction, A(g)$$ \to $$A($$\ell $$);$$\Delta $$H=$$-$$3RT. The correct statement for the reaction is :... JEE Main 2017 (Online) 8th April Morning Slot$$\Delta $$U is equal to JEE Main 2017 (Offline) Given,$${C_{(graphite)}} + {O_2} \to C{O_2}(g)$$;$${\Delta _r}{H^o}$$= - 393.5 kJ mol-1$${{\rm H}_2}(g)$$+$${1 \ov...
JEE Main 2017 (Offline)
If 100 mole of H2O2 decompose at 1 bar and 300 K, the work done (kJ) by one mole of O2(g) as it expands against 1 bar pr...
JEE Main 2016 (Online) 10th April Morning Slot
A reaction at 1 bar is non-spontaneous at low temperature but becomes spontaneous at high temperature. Identify the corr...
JEE Main 2016 (Online) 9th April Morning Slot
The heats of combustion of carbon and carbon monoxide are –393.5 and –283.5 kJ mol–1, respectively. The heat of formatio...
JEE Main 2016 (Offline)
For complete combustion of ethanol, C2H5OH(l) + 3O2(g) $$\to$$ 2CO2(g) + 3H2O(l) the amount of heat produced as measure...
JEE Main 2014 (Offline)
A piston filled with 0.04 mol of an ideal gas expands reversibly from 50.0 mL to 375 mL at a constant temperature of 37....
JEE Main 2013 (Offline)
The incorrect expression among the following is :
AIEEE 2012
The entropy change involved in the isothermal reversible expansion of 2 moles of an ideal gas from a volume of 10 dm3 to...
AIEEE 2011
For a particular reversible reaction at temperature T, ∆H and ∆S were found to be both +ve. If Te is the temperature at ...
AIEEE 2010
The standard enthalpy of formation of NH3 is –46.0 kJ mol–1. If the enthalpy of formation of H2 from its atoms is –436 k...
AIEEE 2010
On the basis of the following thermochemical data : ($$\Delta _fG^oH^+_{(aq)}$$ = 0) H2O(l) $$\to$$ H+(aq) + OH-(aq); $... AIEEE 2009 Standard entropy of X2, Y2 and XY3 are 60, 40 and 50 JK−1 mol−1 , respectively. For the reaction, $${1 \over 2} X_2$$ ... AIEEE 2008 Oxidising power of chlorine in aqueous solution can be determined by the parameters indicated below: $${1 \over 2}C{l_2... AIEEE 2008 Assuming that water vapour is an ideal gas, the internal energy change$$\left( {\Delta U} \right)$$when$$1$$mol of w... AIEEE 2007 Identify the correct statement regarding a spontaneous process AIEEE 2007 In conversion of lime-stone to lime, CaCO3(s)$$\to$$CaO(s) + CO2 (g) the vales of ∆H° and ∆S° are +179.1 kJ mol−1 an... AIEEE 2007 The enthalpy changes for the following processes are listed below: Cl2(g) = 2Cl(g), 242.3 kJ mol–1 I2(g) = 2I(g), 151.... AIEEE 2006 The standard enthalpy of formation$$\Delta _fH^o$$at 298 K for methane, CH4(g), is –74.8 kJ mol–1. The additional info... AIEEE 2006 ($$\Delta H - \Delta U$$) for the formation of carbon monoxide (CO) from its elements at 298 K is (R = 8.314 J K–1 mol–1... AIEEE 2006 An ideal gas is allowed to expand both reversibly and irreversibly in an isolated system. If Ti is the initial temperatu... AIEEE 2006 If the bond dissociation energies of XY, X2 and Y2 (all diatomic molecules) are in the ratio of 1:1:0.5 and$$\Delta H_f... AIEEE 2005 Consider the reaction: N2 + 3H2 $$\to$$ 2NH3 carried out at constant temperature and pressure. If $$\Delta H$$ and $$\De... AIEEE 2005 Consider an endothermic reaction, X$$\to$$Y with the activation energies Eb and Ef for the backward and forward reacti... AIEEE 2005 The enthalpies of combustion of carbon and carbon monoxide are -393.5 and -283 kJ mol-1 respectively. The enthalpy of fo... AIEEE 2004 An ideal gas expands in volume from 1$$\times$$10-3 m3 to 1$$\times$$10-2 m3 at 300 K against a constant pressure of 1... AIEEE 2004 The enthalpy change for a reaction does not depend upon AIEEE 2003 The correct relationship between free energy change in a reaction and the corresponding equilibrium constant Kc is... AIEEE 2003 In an irreversible process taking place at constant T and P and in which only pressure-volume work is being done, the ch... AIEEE 2003 If at 298 K the bond energies of C - H, C - C, C = C and H - H bonds are respectively 414, 347, 615 and 435 kJ/mol, the ... AIEEE 2003 The internal energy change when a system goes from state A to B is 40 kJ/mole. If the system goes from A to B by a rever... AIEEE 2003 A heat engine absorbs heat Q1 at temperature T1 and heat Q2 at temperature T2. Work done by the engine is J (Q1 + Q2). T... AIEEE 2002 The heat required to raise the temperature of body by 1 K is called AIEEE 2002 For the reactions 2C + O2$$\to$$2CO2;$$\Delta H$$= -393 J 2Zn + O2$$\to$$2ZnO;$$\Delta H$$= -412 J... AIEEE 2002 If an endothermic reaction is non-spontaneous at freezing point of water and becomes feasible at its boiling point, then AIEEE 2002 ## Numerical More When 600 mL of 0.2 M HNO3 is mixed with$$400 \mathrm{~mL}$$of 0.1 M NaOH solution in a flask, the rise in temperature ... JEE Main 2022 (Online) 29th July Morning Shift Among the following the number of state variables is __________. Internal energy (U) Volume (V) Heat (q) Enthalpy (H)... JEE Main 2022 (Online) 28th July Evening Shift A gas (Molar mass = 280$$\mathrm{~g} \mathrm{~mol}^{-1}$$) was burnt in excess$$\mathrm{O}_{2}$$in a constant volume ... JEE Main 2022 (Online) 27th July Evening Shift For the reaction$$\mathrm{H}_{2} \mathrm{F}_{2}(\mathrm{~g}) \rightarrow \mathrm{H}_{2}(\mathrm{~g})+\mathrm{F}_{2}(\ma... JEE Main 2022 (Online) 26th July Evening Shift $$2.4 \mathrm{~g}$$ coal is burnt in a bomb calorimeter in excess of oxygen at $$298 \mathrm{~K}$$ and $$1 \mathrm{~atm}... JEE Main 2022 (Online) 26th July Morning Shift While performing a thermodynamics experiment, a student made the following observations. HCl + NaOH$$\to$$NaCl + H2O ... JEE Main 2022 (Online) 25th July Evening Shift The standard free energy change ($$\Delta$$G$$^\circ$$) for 50% dissociation of N2O4 into NO2 at 27$$^\circ$$C and 1 atm... JEE Main 2022 (Online) 25th June Morning Shift The standard entropy change for the reaction 4Fe(s) + 3O2(g)$$\to$$2Fe2O3(s) is$$-$$550 J K$$-$$1 at 298 K. [Given : ... JEE Main 2022 (Online) 25th June Morning Shift A fish swimming in water body when taken out from the water body is covered with a film of water of weight 36 g. When it... JEE Main 2022 (Online) 26th June Evening Shift 2.0 g of H2 gas is adsorbed on 2.5 g of platinum powder at 300 K and 1 bar pressure. The volume of the gas adsorbed per ... JEE Main 2022 (Online) 26th June Morning Shift For complete combustion of methanol CH3OH(I) +$${3 \over 2}$$O2(g)$$\to$$CO2(g) + 2H2O(I) the amount of heat produced... JEE Main 2022 (Online) 26th June Morning Shift When 5 moles of He gas expand isothermally and reversibly at 300 K from 10 litre to 20 litre, the magnitude of the maxim... JEE Main 2022 (Online) 27th June Evening Shift 4.0 L of an ideal gas is allowed to expand isothermally into vacuum until the total volume is 2.0 L. The amount of heat ... JEE Main 2022 (Online) 28th June Morning Shift For combustion of one mole of magnesium in an open container at 300 K and 1 bar pressure,$$\Delta$$CH$$\Theta $$=$$-$...
JEE Main 2022 (Online) 28th June Evening Shift
2.2 g of nitrous oxide (N2O) gas is cooled at a constant pressure of 1 atm from 310 K to 270 K causing the compression o...
JEE Main 2022 (Online) 29th June Evening Shift
A box contains 0.90 g of liquid water in equilibrium with water vapour at 27$$^\circ$$C. The equilibrium vapour pressure...
JEE Main 2022 (Online) 29th June Evening Shift
17.0 g of NH3 completely vapourises at $$-$$33.42$$^\circ$$C and 1 bar pressure and the enthalpy change in the process i...
JEE Main 2022 (Online) 29th June Morning Shift
For the reaction, 2NO2(g) $$\rightleftharpoons$$ N2O4(g), when $$\Delta$$S = $$-$$176.0 JK$$-$$1 and $$\Delta$$H = $$-$$...
JEE Main 2021 (Online) 1st September Evening Shift
Data given for the following reaction is as follows :FeO(s) + C(graphite) $$\to$$ Fe(s) + CO(g) .tg {border-collapse:co...
JEE Main 2021 (Online) 27th August Evening Shift
Two flasks I and II shown below are connected by a valve of negligible volume.When the valve is opened, the final pressu...
JEE Main 2021 (Online) 27th August Evening Shift
200 mL of 0.2 M HCl is mixed with 300 mL of 0.1 M NaOH. The molar heat of neutralization of this reaction is $$-$$57.1 k...
JEE Main 2021 (Online) 27th August Morning Shift
For water $$\Delta$$vap H = 41 kJ mol$$-$$1 at 373 K and 1 bar pressure. Assuming that water vapour is an ideal gas that...
JEE Main 2021 (Online) 26th August Evening Shift
The Born-Haber cycle for KCl is evaluated with the following data :$${\Delta _f}{H^\Theta }$$ for KCl = $$-$$436.7 kJ mo...
JEE Main 2021 (Online) 26th August Morning Shift
When 400 mL of 0.2 M H2SO4 solution is mixed with 600 mL of 0.1 M NaOH solution, the increase in temperature of the fina...
JEE Main 2021 (Online) 27th July Evening Shift
For water at 100$$^\circ$$ C and 1 bar,$$\Delta$$vap H $$-$$ $$\Delta$$vap U = _____________ $$\times$$ 102 J mol$$-$$1....
JEE Main 2021 (Online) 27th July Morning Shift
A system does 200 J of work and at the same time absorbs 150 J of heat. The magnitude of the change in internal energy i...
JEE Main 2021 (Online) 25th July Evening Shift
At 298 K, the enthalpy of fusion of a solid (X) is 2.8 kJ mol$$-$$1 and the enthalpy of vaporisation of the liquid (X) i...
JEE Main 2021 (Online) 25th July Morning Shift
If the standard molar enthalpy change for combustion of graphite powder is $$-$$2.48 $$\times$$ 102 kJ mol$$-$$1, the am...
JEE Main 2021 (Online) 22th July Evening Shift
For a given chemical reaction A $$\to$$ B at 300 K the free energy change is $$-$$49.4 kJ mol$$-$$1 and the enthalpy of ...
JEE Main 2021 (Online) 20th July Evening Shift
For the reaction C2H6 $$\to$$ C2H4 + H2the reaction enthalpy $$\Delta$$rH = __________ kJ mol$$-$$1. (Round off to the...
JEE Main 2021 (Online) 18th March Morning Shift
The standard enthalpies of formation of Al2O3 and CaO are $$-$$1675 kJ mol-1 and $$-$$635 kJ mol$$-$$1 respectively.For ...
JEE Main 2021 (Online) 17th March Morning Shift
The pressure exerted by a non-reactive gaseous mixture of 6.4g of methane and 8.8 g of carbon dioxide in a 10L vessel at...
JEE Main 2021 (Online) 17th March Morning Shift
At 25$$^\circ$$C, 50 g of iron reacts with HCl to form FeCl2. The evolved hydrogen gas expands against a constant pressu...
JEE Main 2021 (Online) 16th March Evening Shift
The average S-F bond energy in kJ mol$$-$$1 of SF6 is __________. (Rounded off to the nearest integer)[Given : The value...
JEE Main 2021 (Online) 26th February Evening Shift
An exothermic reaction X $$\to$$ Y has an activation energy 30 kJ mol$$-$$1. If energy change $$\Delta$$E during the r...
JEE Main 2021 (Online) 26th February Morning Shift
For a chemical reaction A + B ⇌ C + D($${\Delta _r}{H^\Theta }$$ = 80 kJ mol$$-$$1) the entropy change $${\Delta _r}{S^\... JEE Main 2021 (Online) 26th February Morning Shift Five moles of an ideal gas at 293 K is expanded isothermally from an initial pressure of 2.1 MPa to 1.3 MPa against at c... JEE Main 2021 (Online) 25th February Evening Shift The ionization enthalpy of Na+ formation from Na(g) is 495.8 kJ mol$$-$$1, while the electron gain enthalpy of Br is$$-...
JEE Main 2021 (Online) 25th February Morning Slot
The reaction of cyanamide, NH2CN(s) with oxygen was run in a bomb calorimeter and $$\Delta$$U was found to be $$-$$742.2...
JEE Main 2021 (Online) 25th February Morning Slot
For a dimerization reaction, 2A(g) $$\to$$ A2(g) at 298 K, $$\Delta$$Uo = –20 kJ mol–1, $$\Delta$$So = –30 JK–1 mo...
JEE Main 2020 (Online) 5th September Evening Slot
The heat of combustion of ethanol into carbon dioxide and water is – 327 kcal at constant pressure. The heat evolved (in...
JEE Main 2020 (Online) 2nd September Evening Slot
The internal energy change (in J) When 90 g of water undergoes complete evaporation at 100oC is ______. (Given : $$\Delt... JEE Main 2020 (Online) 2nd September Morning Slot A sample of milk splits after 60 min. at 300 K and after 40 min. at 400 K when the population of lactobacillus acidophil... JEE Main 2020 (Online) 9th January Evening Slot A cylinder containing an ideal gas (0.1 mol of 1.0 dm3) is in thermal equilibrium with a large volume of 0.5 molal aqueo... JEE Main 2020 (Online) 9th January Evening Slot At constant volume, 4 mol of an ideal gas when heated from 300 K to 500K changes its internal energy by 5000 J. The mola... JEE Main 2020 (Online) 8th January Evening Slot NaClO3 is used, even in spacecrafts, to produce O2. The daily consumption of pure O2 by a person is 492L at 1 atm, 300K.... JEE Main 2020 (Online) 8th January Evening Slot The magnitude of work done by a gas that undergoes a reversible expansion along the path ABC shown in the figure is ____... JEE Main 2020 (Online) 8th January Morning Slot The standard heat of formation$$\left( {{\Delta _f}H_{298}^0} \right) of ethane (in kj/mol), if the heat of combustio...
JEE Main 2020 (Online) 7th January Evening Slot

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