Thermodynamics PYQs Set 14 (PDF)

Set 14 of 18 · Questions 391-420 of 511

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Mere Teacher · Previous Year Questions JEE Main Chemistry · Thermodynamics · Set 14 (Q391-420)
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391. $The standard enthalpy of formation of CO (g), CO_{2} (g), N_{2} O (g) and N_{2} O_{4} (g) are respectively - 10, - 393, 81 and - 10 kJ mol^{- 1} . Enthalpy change (in kJ) of the following reaction is N_{2} O_{4} (g) + 3 CO (g) ⟶ N_{2} O (g) + 3 CO_{2} (g)$ (1) $-1058$ (2) $+1058$ (3) $-957$ (4) $+957$ 392. $Which reaction is not feasible?$ (1) $2 KI + B r_{2} \to 2 KBr + I_{2}$ (2) $2 KBr + I_{2} \to 2 KI + B r_{2}$ (3) $2 KBr + C l_{2} \to 2 KCl + B r_{2}$ (4) $2 H_{2} O + 2 F_{2} \to 4 HF + O_{2}$ 393. $When ' X' g of graphite is completely burnt in a bomb calorimeter in excess of O_{2} at 298 K and 1 atm pressure as given in the equation C (graphite) + O_{2} (g) \to CO_{2} (g) The temperature of calorimeter raised from 298 K to 302 K . If the heat capacity of the calorimeter and molar enthalpy change for the reaction at 1 atm and 298 K are 20.7 kJ K^{- 1} and - 248.4 kJ mol^{- 1}, ' X' in g is$ (1) $8$ (2) $2$ (3) $3$ (4) $4$ 394. $Identify the invalid equation.$ (1) $Δ H = Σ H_{products} - Σ H_{reactants}$ (2) $Δ H = Δ U + P Δ V$ (3) $Δ H_{(reaction)}^{o} = Δ H_{(product bonds)}^{o} - Δ H_{(reactant bocds)}^{o}$ (4) $Δ H = Δ U + Δ nRT$ 395. $Cell reaction is spontaneous when$ (1) $Δ G^{o} is negative$ (2) $Δ G^{o} is positive$ (3) $Δ E_{red}^{o} is positive$ (4) $Δ E_{red}^{o} is negative.$ 396. $A reaction occurs spontaneously if$ (1) $T Δ S < Δ H and both ΔH and ΔS are +ve$ (2) $T Δ S > Δ H and Δ H is + ve and Δ S is -ve$ (3) $T Δ S > Δ H and both Δ H and Δ S are + ve$ (4) $T Δ S = Δ H and both ΔH and ΔS are +ve$ 397. $Unit of entropy is$ (1) $J K^{- 1} mo l^{- 1}$ (2) $Jmo l^{- 1}$ (3) $J^{- 1} K^{- 1} mo l^{- 1}$ (4) $J Kmo l^{- 1}$ 398. $The following two reactions are known F e_{2} O_{3 (s)} + 3 C O_{(g)} \to 2 F e_{(s)} + 3 C O_{2 (g)}; Δ H = - 26.8 kJ Fe O_{(s)} + C O_{(g)} \to F e_{(s)} + C O_{2 (g)}; Δ H = - 16.5 kJ The value of Δ H for the following reaction F e_{2} O_{3 (s)} + C O_{(g)} \to 2 Fe O_{(s)} + C O_{2 (g)} is$ (1) $+ 10.3 kJ$ (2) $- 43.3 kJ$ (3) $- 10.3 kJ$ (4) $+ 6.2 kJ$ 399. $Given H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (l); Δ H = - 285 kJ N_{2} O_{5} (g) + H_{2} O (l) \to 2 HNO_{3} (l); Δ H = - 76.6 kJ N_{2} (g) + 3 O_{2} (g) + H_{2} (g) \to 2 HNO_{3} (l); Δ H = - 348.2 kJ Calculate the Δ H of 2 N_{2} (g) + 5 O_{2} (g) \to 2 N_{2} O_{5} (g) . [TS / July 19, 2022 (I)]$ (1) $572 kJ$ (2) $419 kJ$ (3) $14.5 kJ$ (4) $26.8 kJ$ 400. $Entropy of the universe is$ (1) $constant$ (2) $zero$ (3) $continuously decreasing$ (4) $continuously increasing.$ 401. $Given below are two statements : One is labelled as Assertion (A) and the other is labelled as Reason (R) Assertion (A) : Enthalpy of neutralisation of strong monobasic acid with strong monoacidic base is always - 57 kJ mol^{- 1} . Reason (R) : Enthalpy of neutralisation is the amount of heat liberated when one mole of H^{+} ions furnished by acid combine with one mole of OH^{-} ions furnished by base to form one mole of water. In the light of the above statements, choose the correct answer from the options given below.$ (1) $(A) is true but (R) is false$ (2) $Both (A) and (R) are true but (R) is not the correct explanation of (A)$ (3) $Both (A) and (R) are true and (R) is the correct explanation of (A)$ (4) $(A) is false but (R) is true$ 402. $C_{2} H_{6} (g) + 3.5 O_{2} (g) \to 2 CO_{2} (g) + 3 H_{2} O (g) Δ S_{vap} (H_{2} O, l) = x_{1} cal K^{- 1} (boiling point = T_{1}) Δ H_{f} (H_{2} O, l) = x_{2} Δ H_{f} (CO_{2}) = x_{3} Δ_{H_{f}} (C_{2} H_{6}) = x_{4} Hence, l H for the reaction is -$ (1) $2 x_{3} + 3 x_{2} - x_{4}$ (2) $2 x_{3} + 3 x_{2} - x_{4} + 3 x_{1} T_{1}$ (3) $2 x_{3} + 3 x_{2} - x_{4} - 3 x_{1} T_{1}$ (4) $x_{1} T_{1} + X_{2} + X_{3} - x_{4}$ 403. $Given : (i) C (graphite) + O_{2} (g) \to CO_{2} (g); Δ_{r} H^{0} = xkJ mol^{- 1} (ii) C (graphite) + \frac{1}{2} O_{2} (g) \to CO (g); Δ_{r} H^{0} = ykJ mol^{- 1} (iii) CO (g) + \frac{1}{2} O_{2} (g) \to CO_{2} (g); Δ_{r} H^{0} = zkJ mol^{- 1} Based on the above thermochemical equations, find out which one of the following algebraic relationships is correct?$ (1) $x = y + z$ (2) $z = x + y$ (3) $y = 2 z - x$ (4) $x = y - z$ 404. $If for the reaction CCl_{4} (g) \to C (g) + 4 Cl (g) the following data is given Δ_{vap} H^{\circ} CCl_{4} (l) = 30 kJ mol^{- 1}, vap = vaporization Δ_{f} H^{\circ} CCl_{4} = - 136.0 kJ mol^{- 1}, f = formation Δ_{a} H_{C} = 714.0 kJ mol^{- 1}, a = atomization Δ_{a} H^{\circ} Cl_{2} = 242.0 kJ mol^{- 1}, a = atomization the bond mean enthalpy of C - Cl in CCl_{4} (1) is$ (1) $-319$ (2) $326$ (3) $-326$ (4) $292$ 405. $From the following data at 25^{\circ} C, calculate the Δ_{r} H^{0} for H_{2} O (g) \to 2 H (g) + O (g) . reaction: Δ_{r} H^{0} (kJ mol^{- 1}) \frac{1}{2} H_{2} (g) + \frac{1}{2} O_{2} (g) \to OH (g) 42.09 H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (g) - 242 H_{2} (g) \to 2 H (g) 436 O_{2} (g) \to 2 O (g) 496$ (1) $1174 kJ mol^{- 1}$ (2) $742 kJ mol^{- 1}$ (3) $926 kJ mol^{- 1}$ (4) $690 kJ mol^{- 1}$ 406. $Which of the following is not correct?$ (1) $Δ G is negative for a spontaneous reaction$ (2) $Δ G is positive for a spontaneous reaction$ (3) $Δ G is zero for a reversible reaction$ (4) $Δ G is positive for a non-spontaneous reaction$ 407. $Three thermochemical equations are given below (i) C_{(graphite)} + O_{2 (g)} \to C O_{2 (g)}; Δ_{r} H^{O} = x kJ mo l^{- 1} (ii) C_{(graphite)} +^{1} /_{2} O_{2 (g)} \to C O_{(g)}; Δ_{r} H^{O} = y kJ mo l^{- 1} (iii) C O_{(g)} + 1 /_{2} O_{2 (g)} \to C O_{2 (g)}; Δ_{r} H^{O} = z kJ mo l^{- 1} Based on the above equations, find out which of the relationship given below is correct.$ (1) $z = x + y$ (2) $x = y + z$ (3) $y = 2 z - x$ (4) $x = y - z$ 408. $The law formulated by Dr. Nernst is$ (1) $First law of thermodynamics$ (2) $Second law of thermodynamics$ (3) $Third law of thermodynamics$ (4) $Both (a) and (b)$ 409. $At standard conditions, if the change in the enthalpy for the following reaction is - 109 kJ mol^{- 1} H_{2} (g) + Br_{2} (g) \to 2 HBr (g) Given that bond energy of H_{2} and Br_{2} is 435 kJ mol^{- 1} and 192 kJ mol^{- 1}, respectively, what is the bond energy (in kJ mol^{- 1}) of HBr?$ (1) $736$ (2) $518$ (3) $259$ (4) $368$ 410. $Isentropic process is$ (1) $adiabatic and irreversible process$ (2) $isothermal and reversible process$ (3) $adiabatic and reversible process$ (4) $isothermal and reversible for which Q = 0$ 411. $The entropy change when two moles of ideal monoatomic gas is heated from 200 to 30 0^{0} C reversibly and isochoric ally?$ (1) $\frac{3}{2} R ln (\frac{300}{200})$ (2) $\frac{5}{2} R ln (\frac{573}{273})$ (3) $3 R ln (\frac{573}{473})$ (4) $\frac{3}{2} R ln (\frac{573}{473})$ 412. $If the enthalpy of sublimation of Li is 155 kJ mol^{- 1}, enthalpy of dissociation of F_{2} is 150 kJ mol^{- 1}, ionization enthalpy of Li is 520 kJ mol^{- 1}, electron gain enthalpy of F is - 313 kJ mol^{- 1}, standard enthalpy of formation of LiF is - 594 kJ mol^{- 1} . The magnitude of lattice enthalpy of LiF is kJmol^{- 1} . (Nearest Integer)$ 413. $The number of incorrect statement/s about the black body from the following is______(a) Emit or absorb energy in the form of electromagnetic radiation. (b) Frequency distribution of the emitted radiation depends on temperature. (c) At a given temperature, intensity vs frequency curve passes through a maximum value. (d) The maximum of the intensity vs frequency curve is at a higher frequency at higher temperature compared to that at lower temperature.$ 414. $Consider the following cases of standard enthalpy of reaction (Δ H_{r}^{\circ}) in (kJmol^{- 1}) C_{2} H_{6} (g) + \frac{7}{2} O_{2} (g) \to 2 CO_{2} (g) + 3 H_{2} O (l) Δ H_{1}^{\circ} = - 1550 C (graphite) + O_{2} (g) \to CO_{2} (g) Δ H_{2}^{\circ} = - 393.5 The magnitude of Δ H_{f C_{2} H_{6} (g)}^{\circ} is H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (l) Δ H_{3}^{\circ} = - 286 kJmol^{- 1} (Nearest integer).$ 415. $Combustion of 1 mole of benzene is expressed at C_{6} H_{6} (l) + \frac{15}{2} O_{2} (g) \to 6 CO_{2} (g) + 3 H_{2} O (l) . The standard enthalpy of combustion of 2 mol of benzene is -^{’} x^{’} kJ . x =_________Given: 1. standard Enthalpy of formation of 1 mol of C_{6} H_{6} (l), for the reaction 6 C (graphite) + 3 H_{2} (g) \to C_{6} H_{6} (l) is 48.5 kJ mol^{- 1} 2. Standard Enthalpy of formation of 1 mol of CO_{2} (g), for the reaction C (graphite) + O_{2} (g) \to CO_{2} (g) is - 393.5 kJ mol^{- 1} . 3. Standard and Enthalpy of formation of 1 mol of H_{2} O (l), for the reaction H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (l) is - 286 kJ mol^{- 1} .$ 416. $Use the following data: Substance \frac{Δ _{f} H ^{⊖} ( 500 K )}{kJmol ^{- 1}} \frac{S ^{⊖} ( 500 K )}{JK ^{- 1} mol ^{- 1}} AB (g) 32222 A_{2} (g) 6146 B_{2} (g) x 280 One mole each of A_{2} (g) and B_{2} (g) are taken in a 1 L closed flask and allowed to establish the equilibrium at 500 K . A_{2} (g) + B_{2} (g) ⇌ 2 AB (g) The value of x (inkJmol^{- 1}) is____. (Nearest integer) (Given: log K = 2.2 R = 8.3 J K^{- 1} mol^{- 1})$ 417. $Assuming ideal behavior, the magnitude of log K for the following reaction at 25° C is x \times 10^{- 1} . The valueof x is ____.(Integer answer) 3 HC \equiv C H_{(g)} ⇌ C_{6} H_{6 (l)} (Given : ∆_{f} G ° (HC \equiv CH) = - 2.04 \times 10^{5}) mo l^{- 1}; ∆_{f} G ° (C_{6} H_{6}) = - 1.24 \times 10^{5} Jmo l^{- 1} (R = 8.314 J K^{- 1} mo l^{- 1})$ 418. $0.3 g of ethane undergoes combustion at 27°C in a bomb calorimeter. The temperature of calorimeter system (including the water) is found to rise by 0.5°C The heat evolved during combustion of ethane at constant pressure is________kJ m o l^{- 1} .(Nearest integer) [Given : The heat capacity of the calorimeter system is 20 kJ K^{- 1}, R = 8.3 J K^{- 1} m o l^{- 1};Assume ideal gas behaviour. Atomic mass of C and H are 12 and 1 g m o l^{- 1} respectively]$ 419. $40% of HI undergoes decomposition to H_{2} and I_{2} at 300 K. Δ G^{\circ} for this decomposition reaction at one atmosphere pressure is________ J m o l^{- 1} . [nearest integer] (Use R = 8.31 J K^{- 1} m o l^{- 1}; log 2 = 0.3010, ln 10 = 2.3, log 3 = 0.477)$ 420. $When 400mL of 0.2 M H_{2} S O_{4} solution is mixed with of solution, the increase in temperature of the final solution is - 1 0^{- 2} K . (Round off to the nearest integer). [Use: H^{+} (a q) + O H^{-} (a q) \to H_{2} O : Δ_{r} H = - 57.1 k J m o l^{- 1}] Specific heat of H_{2} O = 4.18 J K^{- 1} g^{- 1} density of H_{2} O = 1.0 g c m^{- 3} Assume no change in volume of solution on mixing.$