Thermodynamics PYQs Set 9 (PDF)

Set 9 of 18 · Questions 241-270 of 511

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Mere Teacher · Previous Year Questions JEE Main Chemistry · Thermodynamics · Set 9 (Q241-270)
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241. $2 Zn + O_{2} \to 2 ZnO; Δ G^{o} = - 616 J 2 Zn + S_{2} \to 2 ZnS; Δ G^{o} = - 293 J S_{2} + 2 O_{2} \to 2 S O_{2}; Δ G^{o} = - 408 J Δ G^{o} for the following reaction 2 ZnS + 3 O_{2} \to 2 ZnO + 2 S O_{2} is$ (1) $- 731 J$ (2) $- 1317 J$ (3) $- 501 J$ (4) $+ 731 J$ 242. $6 g of graphite is burnt in a bomb calorimeter at 25^{\circ} C and 1 atm pressure. The temperature of water increased from 25^{\circ} C to 31^{\circ} C . If Δ H of this reaction is - 248 kJ mol^{- 1}, find out C_{V} (in kJ K^{- 1}) of bomb calorimeter.$ (1) $20.667$ (2) $41.33$ (3) $1488$ (4) $0.145$ 243. $For irreversible expansion of an ideal gas under isothermal condition, the correct option is:$ (1) $Δ U \neq = 0, Δ S_{total} \neq = 0$ (2) $Δ U = 0, Δ S_{total} \neq = 0$ (3) $Δ U \neq = 0, Δ S_{total} = 0$ (4) $Δ U = 0, Δ S_{total} = 0$ 244. $The heats of combustion of carbon and carbon monoxide are -393.5 and -283.5 kJ m o l^{-1}, respectively. The heat of formation (in kJ) of carbon monoxide per mole is :$ (1) $676.5$ (2) $- 676.5$ (3) $-110.5$ (4) $110.5$ 245. $For a diatomic ideal gas in a closed system, which of the following plots does not correctly describe the relation between various thermodynamic quantities?$ (1) (2) (3) (4) 246. $The correct option for free expansion of an ideal gas under adiabatic condition is:$ (1) $q = 0, Δ T < 0 and w>0$ (2) $q < 0, Δ T = 0 and w=0$ (3) $q > 0, Δ T > 0 and w>0$ (4) $q = 0, Δ T = 0 and w=0$ 247. $Three moles of an ideal gas expanded spontaneously into vacuum. The work done will be$ (1) $infinite$ (2) $3 Joules$ (3) $9 Joules$ (4) $zero$ 248. $The enthalpy of fusion of water is 1.435 kcal/mol. The molar entropy changes for the melting of ice at 0^{o} C is$ (1) $10.52 cal/ (mol K)$ (2) $21.04 cal/ (mol K)$ (3) $5.260 cal/ (mol K)$ (4) $0.526 cal/ (mol K)$ 249. $Conversion of oxygen into ozone is non spontaneous at$ (1) $all temperatures$ (2) $high temperature$ (3) $room temperature$ (4) $low temperature.$ 250. $Which of the following options are correct? A B C D Δ_{r} H^{\circ} + + - + Δ S^{\circ} + + - - Δ_{r} G^{\circ} + - - + Spontaneity of the reaction Spontaneous at low T Spontaneous at high Spontaneous at low T Spontaneous at high T$ (1) $A, B and C$ (2) $B only$ (3) $B and C$ (4) $C and D$ 251. $Among the following, the set of parameters that represents path functions, is: (i) q + w (ii) q (iii) w (iv) H - TS$ (1) $(ii) and (iii)$ (2) $(ii), (iii) and (iv)$ (3) $(i) and (iv)$ (4) $(i), (ii) and (iii)$ 252. $For a reaction, A(g) ® A (l); DH = -3RT. The correct statement for the reaction is:$ (1) $DH = DU ¹ O$ (2) $\|DH\| > \|DU\|$ (3) $\|DH\| < \|DU\|$ (4) $DH = \|DU = O$ 253. $The bond enthalpies of heavy hydrogen, O - O and D - O are + 400, + 498 and + 490 kJ mol^{- 1}, respectively. The Δ H^{\circ} of the reaction to produce D_{2} O is$ (1) $- 300 kJ mol^{- 1}$ (2) $- 331 kJ mol^{- 1}$ (3) $29.1 kJ mol^{- 1}$ (4) $2.91 kJ mol^{- 1}$ 254. $The variation of equilibrium constant with temperature is given below: Temperature Equilibrium Constant T_{1} = 25°C K_{1} = 10 T_{2} = 100°C K_{2} = 100 The values of ∆ H°, ∆ G° at T_{1} and ∆ G° at T_{2} (in kJ mo 1^{- 1}) respectively, are close to [Use R = 8.314J K^{- 1} mo 1^{- 1}]$ (1) $28.4,-5.71 and -14.29$ (2) $0.64,-7.14 and -5.71$ (3) $28.4,-7.14 and -5.71$ (4) $0.64,-5.71 and -14.29$ 255. $Ice at - 5^{\circ} C is heated to become vapor with temperature of 110^{\circ} C at atmospheric pressure. The entropy change associated with this process can be obtained from$ (1) $\int_{268 K}^{273 K} C_{p}, mdT + \frac{Δ H _{m} , fusion}{T _{f}} + \frac{Δ H _{m} , vaporisation}{T _{b}} + \int_{273 K}^{373 K} C_{p}, mdT + \int_{373 K}^{383 K} C_{p}, mdT$ (2) $\int_{268 K}^{273 K} \frac{C p , m}{T} dT + \frac{Δ H _{m} , fusion}{T _{f}} + \frac{Δ H _{m} , vaporisation}{T _{b}} + \int_{273 K}^{373 K} \frac{C _{p, m} dT}{T} + \int_{373 K}^{383 K} \frac{C _{p, m} dT}{T}$ (3) $\int_{268 K}^{383 K} C_{p} dT + \frac{q rev}{T}$ (4) $\int_{268 K}^{383 K} C_{p} dT + \frac{Δ H _{melting}}{273} + \frac{Δ H _{boiling}}{373}$ 256. $A liquid when kept inside a thermally insulated closed vessel at 25^{\circ} C was mechanically stirred from outside. What will be the correct option for the following thermodynamic parameters?$ (1) $Δ U < 0, q = 0, w > 0$ (2) $Δ U = 0, q = 0, w = 0$ (3) $Δ U > 0, q = 0, w > 0$ (4) $Δ U = 0, q < 0, w > 0$ 257. $Consider the following data: Δ_{f} H^{⊖} (methane, g) = - XkJmol^{- 1} Enthalpy of sublimation of graphite = YkJmol^{- 1} Dissociation enthalpy of H_{2} = ZkJmol^{- 1} The bond enthalpy of C - H bond is given by :$ (1) $- X + Y + Z 4$ (2) $\frac{X + Y + 4 Z}{2}$ (3) $\frac{X + Y + 2 Z}{4}$ (4) $X + Y + Z$ 258. $Match List I (Equations) with List II (Type of processes) and select the correct option. List I Equations A. K_{p} > Q B. Δ G^{o} < RT ln Q C. K_{p} = Q D. T > \frac{Δ H}{Δ S} List II Type of processes (i) Non-spontaneous (ii) Equilibrium (iii) Spontaneousand endothermic (iv) Spontaneous$ (1) $A - (i), B‐(ii), C‐(iii), D‐(iv)$ (2) $A‐(iii), B‐(iv), C‐(ii), D - (i)$ (3) $A‐(iv), B - (i), C‐(ii), D‐(iii)$ (4) $A‐(ii), B - (i), C‐(iv), D‐(iii)$ 259. $For the reaction, X_{2} O_{4 (l)} \to 2 X O_{2 (g)} Δ U = 2.1 kcal, Δ S = 20 cal K^{- 1} at 300 K Hence, Δ G is$ (1) $2.7 kcal$ (2) $- 2.7 kcal$ (3) $9.3 kcal$ (4) $- 9.3 kcal$ 260. $Which of the following statement is true. The entropy of the universe$ (1) $Increases and tends towards maximum value$ (2) $Decreases and tends to be zero$ (3) $Remains constant$ (4) $Decreases and increases with a periodic rate$ 261. $Consider the following processes: Δ H (kJ / mol) 1/2 A \to B + 150 3 B \to 2 C + D - 125 E + A \to 2 D + 350 For B + D \to E + 2 C, Δ H will be$ (1) $525 kJ/mol$ (2) $- 175 kJ/mol$ (3) $- 325 kJ/mol$ (4) $325 kJ/mol$ 262. $Which of the following is correct option for free expansion of an ideal gas under adiabatic condition?$ (1) $q = 0, Δ T \neq = 0, w = 0$ (2) $q \neq = 0, Δ T = 0, w = 0$ (3) $q = 0, Δ T = 0, w = 0$ (4) $q = 0, Δ T < 0, w \neq = 0$ 263. $At 500 K for an isobaric process. D S_{sy s t e m} = - 10 \frac{k J}{m o l K} and D S_{s u r r} = 12 \frac{k J}{m o l K} Therefore, DG for the entire process is-$ (1) $-500 kJ/mol$ (2) $-1000 kJ/mol$ (3) $-600 kJ/mol$ (4) $-1100 kJ/mol$ 264. $Enthalpy of hydrogenation of one mole of benzene to cyclohexane is [Resonance energy of benzene = - 150.4 kJ / mol, enthalpy of hydrogenation of cyclohexene = - 119.5 kJ / mol]$ (1) $- 208.1 kJ / mol$ (2) $- 358.1 kJ / mol$ (3) $+ 150.4 kJ / mol$ (4) $- 269.9 kJ / mol$ 265. $Assuming enthalpy of combustion of hydrogen at 273 K, - 286 kJ and enthalpy of fusion of ice at the same temperature to be + 6.0 kJ, calculate enthalpy change during formation of 100 g of ice.$ (1) $+ 1622 kJ$ (2) $- 1622 kJ$ (3) $+ 292 kJ$ (4) $- 292 kJ$ 266. $Consider the given data: (i) HCl (g) + 10 H_{2} O (l) \to HCl \cdot 10 H_{2} O Δ H = - 69.01 kJ mol^{- 1} (ii) HCl (g) + 40 H_{2} O (l) \to HCl . 40 H_{2} O Δ H = - 72.79 kJ mol^{- 1} Choose the correct statement: The heat of dilution for the$ (1) $HCl (HCl_{1} 10 H_{2} O) to (HCl . 40 H_{2} O) is 3.78 kJ mol^{- 1} .$ (2) $Dissolution of gas in water is an endothermic process.$ (3) $The heat of solution depends on the amount of solvent.$ (4) $The heat of formation of HCl solution is represented by both (i) and (ii)$ 267. $An ideal gas, C_{v} = \frac{5}{2} R, is expanded adiabatically against a constant pressure of 1 atm untill it doubles in volume. If the initial temperature and pressure is 298 K and 5 atm, respectively then the final temperature is _______K (nearest integer). [C_{v} is the molar heat capacity at constant volume]$ 268. $When Δ H_{vap} = 30 kJ / mol and Δ S_{vap} = 75 J mol^{- 1} K^{- 1}, then the temperature of vapour, at one atmosphere is ______K.$ 269. $30.4 kJ of heat is required to melt one mole of sodium chloride and the entropy change at the melting point is 28.4 J K^{- 1} m o l^{- 1} at 1 atm. The melting point of sodium chloride is_______K (Nearest Integer)$ 270. $The equilibrium constant for a reaction is 10. What will be the magnitude value of ΔGº ? R = 8.31 J K^{-1} m o l^{-1}, T = 314 K. (Approximate integer value in KJ m o l^{-1})$