JEE Main 35 Year PYQs- Thermodynamics - Free MCQ Test with solutions [Updated]

If an endothermic reaction is non-spontaneous at freezing point of water and becomes feasible at its boiling point, then

A heat engine abosrbs heat Q₁ at temperature T₁ and heat Q₂ at temperature T₂. Work done by the engine is J (Q₁ + Q₂). This data [2002]  

For the reactions, [2002] 2C + O₂ → 2CO₂ ; ΔH = -393 J
2Zn + O₂ → 2ZnO ; ΔH = -412 J 

The heat required to raise the temperature of body by 1 K is called [2002]

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 reversible path and returns to state A by an irreversible path what would be the net change in internal energy ? [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^–1, the value of enthalpy change for the reaction H₂C = CH₂(g) + H₂(g) → H₃C — CH₃(g) at 298 K will be [2003] 

In an irreversible process taking place at constant T and P and in which only pressure-volume work is being done, the change in Gibbs free energy (ΔG) and  change in entropy (dS), satisfy the criteria [2003]  

The correct relationship between free energy change in a reaction and the corresponding equilibrium constant K_c is [2003] 

The enthalpy change for a reaction does not depend upon [2003]

An ideal gas expands in volume from 1×10^–3 to 1 × 10^–2 m³ at 300 K against a constant pressure of 1×10⁵ Nm^–2. The work done is [2004] 

The enthalpies of combustion of carbon and carbon monoxide are – 393.5 and – 283 kJ mol^–1 respectively. The enthalpy of formation of carbon monoxide per mole is  

Consider an endothermic reaction X → Y with the activation en er gies E_b and E_f  for the backward and forward reactions, respectively. In general [2005]  

Consider the reaction : N₂ + 3H₂ → 2 NH₃ carried out at constant temperature and pressure. If ΔH and ΔU are the enthalpy and internal energy changes for the reaction, which of the following expressions is true ? [2005]  

If the bond dissociation energies of XY, X ₂ and Y₂ (all diatomic molecules) are in the ratio of 1 : 1 : 0.5 and ΔH_f for the for mation of XY is – 200 kJ mole ^-1 . The bond dissociation energy of X₂ will be [2005]  

An ideal gas is allowed to expand both reversibly and irreversibly in an isolated system. If T_i is the initial temperature and T_f is the final temperature, which of the following statements is correct? [2006] 

The standard enthalpy of formation (D_fHº) at 298 K for methane, CH₄(g) is –74.8 kJ mol^–1. The additional information required to determine the average energy for C – H bond formation would be [2006]  

The enthalpy changes for the following processes are listed below :      [2006]
Cl₂(g) → 2Cl(g), 242.3 kJ mol^–1
I₂(g) → 2I(g), 151.0 kJ mol^–1  
ICl(g) → I(g) + Cl(g), 211.3 kJ mol^–1I₂(s) → I₂(g), 62.76 kJ mol^–1
Given that the standard states for iodine and chlorine are I₂(s) and Cl₂(g), the standard enthalpy of formation for ICl(g) is : [2006]

(ΔH – ΔU) for the formation of carbon monoxide (CO) from its elements at 298 K is [2006] (R = 8.314 J K^–1 mol^–1) 

In conversion of lime-stone to lime, CaCO₃ (s) → CaO(s)+ CO₂(g) the values of ΔH° and ΔS° are + 179.1 kJ mol^-1 and 160.2 J/K respectively at 298 K and 1 bar. Assuming that ΔH° and ΔS° do not change with temperature, temperature above which conversion of limestone to lime will be spontaneous is [2007]  

Assuming that water vapour is an ideal gas, the internal energy change (ΔU) when 1 mol of water is vapourised at 1 bar pressure and 100°C, (given : molar enthalpy of vapourisation of water at 1 bar and 373 K = 41 kJ mol^–1 and R = 8.3 J mol^–1 K^–1) will be [2007] 

Identify the correct statement regarding a spontaneous process: [2007]

Oxidising power of chlorine in aqueous solution can be determined by the parameters indicated below:

(using the data,

will be [2008] 

Standard entropy of X₂, Y₂ and X Y₃ are 60, 40 and 50 J K^–1 mol^–1, respectively. For the reaction,

, to be at equilibrium, the temperature will be [2008]  

On the basis of the following thermochemical data : 
(Δ _f G°H⁺ _​(aq)= 0) [2009]  

= 57.32kJ

= –286.20kJ

The value of enthalpy of formation of OH^– ion at 25° C is: 

The standard enthalpy of for mation of NH₃ is – 46.0 kJ mol^–1. If the enthalpy of formation of H₂ from its atoms is – 436 kJ mol^–1 and that of N₂ is – 712 kJ mol^–1, the average bond enthalpy of N – H bond in NH₃ is [2010]  

For a particular reversible reaction at temperature T, ΔH and ΔS were found to be both +ve. If Te is the temperature at equilibrium, the reaction would be spontaneous when [2010] 

The entropy change involved in the isothermal reversible expansion of  2 mole of an ideal gas from a volume of 10 dm³ to a volume of 100 dm3 at 27°C is: [2011]  

The incorrect expression among the following is : [2012] 

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 37.0ºC. As it does so, it absorbs 208 J of heat. The values of q and w for the process will be: [JEE M 2013]
(R = 8.314 J/mol K) (ln 7.5 = 2.01) 

For complete combustion of ethanol, C₂H₅OH (l) + 3O₂(g)—​→ 2CO₂ ( g)+ 3H₂O (l), the amount of heat produced as measured in bomb calorimeter, is 1364.47 kJ mol^–1 at 25ºC.  Assuming ideality the enthalpy of combustion, Δ_cH, for the reaction will be: (R = 8.314 kJ mol^–1)         [JEE M 2014]