Thermodynamics PYQs Set 9 (PDF)

Set 9 of 14 · Questions 241-270 of 393

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Mere Teacher · Previous Year Questions NEET Chemistry · Thermodynamics · Set 9 (Q241-270)
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241. $If standard molar enthalpy change and standard molar internal energy change measured in bomb calorimeter are equal, which one of the following statements is correct?$ (1) $Δ n > 0, with increase in pressure$ (2) $Δ n > 0, with decrease in pressure$ (3) $Δ n < 0, with increase in pressure$ (4) $Δ n = 0, at constant pressure$ 242. $Which of the following are not state functions? (I) q + w (II) q (III) w (IV) H - TS$ (1) $(I), (II) and (III)$ (2) $(II) and (III)$ (3) $(I) and (IV)$ (4) $(II), (III) and (IV)$ 243. $At 298.2 the relationship between enthalpy of bond dissociation (in k J m o l^{- 1}) for hydrogen (_{H}^{E}) and its isotope, deuterium (_{D}^{E}), is best described by:$ (1) $E_{H} = \frac{1}{2} E_{D}$ (2) $E_{H} = E_{D}$ (3) $E_{H} = E_{D} - 7.5$ (4) $E_{H} = 2 E_{D}$ 244. $Which of the following is not an intensive property?$ (1) $Entropy$ (2) $Melting point$ (3) $Specific gravity$ (4) $Refractive index$ 245. $Which one of the following process is non-spontaneous?$ (1) $Dissolution of C u S O_{4} in water$ (2) $Reaction between H_{2} and O_{2} to form water$ (3) $Water flowing down hill$ (4) $Flow of electric current from low potential to high potential$ 246. $If the enthalpy and entropy change for a reaction at 298 K are - 145 kJ mol^{- 1} and - 650 J K^{- 1} mol^{- 1} respectively, which one of the following statements is correct?$ (1) $Δ G = - 50 kJ mol^{- 1}, the reaction is spontaneous$ (2) $Δ G = - 48.7 kJ mol^{- 1}, the reaction is nonspontaneous$ (3) $Δ G = + 50 kJ mol^{- 1}, the reaction is spontaneous$ (4) $Δ G = 48.7 kJ mol^{- 1}, the reaction is non-spontaneous$ 247. $If Δ G and Δ S for the reaction A (g) \to B (g) + 2 C (g) at 2000 K are - 40 kJ mol^{- 1} and 0.22 kJ K^{- 1} mol^{- 1} respectively, the change in internal energy for the same reaction approximately (in kJ mol^{- 1}) is$ (1) $366.7$ (2) $-33736$ (3) $433.3$ (4) $-433.3$ 248. $Given Δ H_{r}^{\circ} for CO_{2} (g), CO (g) and H_{2} O (g) are -393.5, -110.5 and - 241.8 kJ mol^{- 1}, respectively. The Δ H_{r}^{\circ} (in kJ mol^{- 1}) for the reaction CO_{2} (g) + H_{2} (g) ⟶ CO (g) + H_{2} O (g) is$ (1) $524.1$ (2) $-262.5$ (3) $-41.7$ (4) $41.2$ 249. $Which of the following is the least random state of water$ (1) $Ice$ (2) $Liquid water$ (3) $Steam$ (4) $All present same random state$ 250. $In which of the following conditions a chemical reaction can not occur$ (1) $∆ H and ∆ S increase and T ∆ S > ∆ H$ (2) $∆ H and ∆ S decrease and ∆ H > T ∆ S$ (3) $∆ H increases and ∆ S decreases$ (4) $∆ H decreases and ∆ S increases$ 251. $If for a certain reaction Δ_{r} H is 30 kJ mol^{- 1} at 450 K , the value of Δ_{r} S (in JK^{- 1} mol^{- 1}) for which the same reaction will be spontaneous at the same temperature is$ (1) $-33$ (2) $33$ (3) $-70$ (4) $70$ 252. $Combustion of sucrose is used by aerobic organisms for providing energy for the life sustaining processes. If all the capturing of energy from the reaction is done through electrical process (non P-V work) then calculate maximum available energy which can be captured by combustion of 34.2 g of sucrose Given : ∆ H_{co mb u s t i o n} (sucrose) = - 6000 kJ m o l^{-1} ∆ S_{co mb u s t i o n} = 180 J/K - mol and body temperature is 300 K$ (1) $600 kJ$ (2) $594.6 KJ$ (3) $5.4 kJ$ (4) $605.4 kJ$ 253. $Given that, C (s) + O_{2} (g) ⟶ CO_{2} (g); Δ H^{\circ} = - x kJ mol^{- 1} 2 CO (g) + O_{2} (g) ⟶ 2 CO_{2} (g); Δ H^{\circ} = - y kJ mol^{- 1} The enthalpy of formation of CO will be$ (1) $\frac{y - 2 x}{3}$ (2) $\frac{y - 2 x}{2}$ (3) $\frac{2 x - y}{2}$ (4) $\frac{x - y}{2}$ 254. $Which of the followings is not a state function?$ (1) $Internal Energy$ (2) $Work$ (3) $Enthalpy$ (4) $Entropy$ 255. $Change in enthalpy for reaction, 2 H_{2} O_{2 (l)} \to 2 H_{2} O_{(l)} + O_{2 (g)} if heat of formation of H_{2} O_{2 (l)} and H_{2} O_{(l)} are - 188 and - 286 kJ/mol respectively, is$ (1) $- 196 kJ/mol$ (2) $+ 196 kJ/mol$ (3) $+ 948 kJ/mol$ (4) $- 948 kJ/mole$ 256. $Statement-1 : For every chemical reaction at equilibrium, standard Gibbs energy of reaction is zero. Statement-2 : At constant temperature and pressure, chemical reactions are spontaneous in the direction of decreasing Gibbs energy.$ (1) $Statement-1 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement-$ (2) $Statement-1 is True, Statement-2 is True; Statement-2 is NOT a correct explanation for Statement-1$ (3) $Statement-1 is True, Statement-2 is False$ (4) $Statement-1 is False, Statement-2 is True$ 257. $Considering the reaction : C_{(s)} + O_{2 (g)} \to CO_{2 (g)} + 393.5 kJ the signs of Δ H, Δ S and Δ G respectively are$ (1) $+,-,-$ (2) $-,+,+$ (3) $-,-,-$ (4) $-,+,-$ 258. $500 J of energy is transferred as heat to 0.5 mol of Argon gas at 298 K and 1.00 atm. The final temperature and the change in internal energy respectively are: Given : R = 8.3 J K^{- 1} m o l^{- 1}$ (1) $378 K and 500 J$ (2) $368 K and 500 J$ (3) $348 K and 300 J$ (4) $378 K and 300 J$ 259. $For the reversible reaction: A_{(s)} + B_{(g)} ⇌ C_{(g)} + D_{(g)} : Δ G^{\circ} = - 350 kJ . Which one of the following statements is true?$ (1) $The entropy change is negative.$ (2) $Equilibrium constant is greater than one.$ (3) $The reaction should be instantaneous.$ (4) $The reaction is thermodynamically not feasible.$ 260. $When two mole of an ideal gas heated from 300 K to 600 K at constant pressure. The change in entropy of gas (∆ S) is :$ (1) $\frac{3}{2} R ln 2$ (2) $-R \frac{3}{2} ln 2$ (3) $5R ln 2$ (4) $\frac{5}{2} R ln 2$ 261. $When one mole of an ideal gas is compressed to half of its initial volume and simultaneously heated to twice its initial temperature, the change in entropy of gas (∆ S) is :$ (1) $C_{p, m} ln 2$ (2) $C_{v, m} ln 2$ (3) $R ln 2$ (4) $(C_{v, m} - R) ln 2$ 262. $Consider the Born-Haber cycle for the formation of an ionic compound given below and identify the compound (Z) formed.$ (1) $MX$ (2) $M^{+} X_{(g)}^{-}$ (3) $M^{+} X$ (4) $none of these$ 263. $Consider the given plot of enthalpy of the following reaction between A and B, A + B \to C + D Identify the incorrect statement$ (1) $Activation enthalpy to form C is 5 kJ mol^{- 1} less than that to form D.$ (2) $C is the thermodynamically stable product.$ (3) $D is kinetically stable product.$ (4) $Formation of A and B from C has highest enthalpy of activation.$ 264. $Total enthalpy change for freezing of 1 mol of water at 10^{\circ} C to ice at - 10^{\circ} C is . (Given: Δ_{fus} H = \frac{x kJ}{mol} C_{p} (H_{2} O (l)) = y J mol^{- 1} K^{- 1} C_{p} (H_{2} O (s)) = z J mol^{- 1} K^{- 1}$ (1) $- x - 10 y - 10 z$ (2) $x - 10 y - 10 z$ (3) $- 10 (100 x + y + z)$ (4) $10 (100 x + y + z)$ 265. $A certain mass of a gas was brought from state A to B by following three different paths, namely 1,2 and 3 respectively. Which of the following relations is correct for the work done?$ (1) $W_{1} = W_{2} = W_{3}$ (2) $W_{1} < W_{2} < W_{3}$ (3) $W_{1} > W_{2} > W_{3}$ (4) $W_{1} = W_{2} < W_{3}$ 266. $For complete combustion of ethanol, C2H5OH(l) + 3 O_{2} (g) \to 2 C O_{2} (g) + 3H2O(l), the amount of heat produced as measured in bomb calorimeter, is 1364.47 kJ mol^{- 1} at 25°C. Assuming ideality the Enthalpy of combustion, ΔCH, for the reaction will be : (R = 8.314 J mol^{- 1})$ (1) $- 1366.95 kJ m o l^{-1}$ (2) $- 1361.95 kJ m o l^{-1}$ (3) $- 1460.50 kJ m o l^{-1}$ (4) $- 1350.50 kJ m o l^{-1}$ 267. $Given (A) 2CO(g)+ O_{2} (g) \to 2 C O_{2} (g) Δ H_{1}^{0} = -x kJ m o l^{- 1} (B) C(graphite)+ O_{2} (g) \to C O_{2} (g) Δ H_{2}^{0} = -y kJ m o l^{- 1} The ∆ H° for the reaction C (graphite)+ 12 O_{2} (g) \to CO(g) is$ (1) $\frac{2 x - y}{2}$ (2) $\frac{x + 2 y}{2}$ (3) $\frac{x - 2 y}{2}$ (4) $2y - x$ 268. $Two vessels A and B are connected via stopcock. The vessel A is filled with a gas at a certain pressure. The entire assembly is immersed in water and is allowed to come to thermal equilibrium with water. After opening the stopcock the gas from vessel A expands into vessel B and no change in temperature is observed in the thermometer. Which of the following statement is true?$ (1) $dq \neq = 0$ (2) $The pressure in the vessel B before opening the stopcock is zero$ (3) $dw \neq = 0$ (4) $dU \neq = 0$ 269. $At 25°C and 1 atm pressure, the enthalpy of combustion of benzene (1) and acetylene (g) are -3268 kJ m o l^{- 1} and -1300 kJ m o l^{- 1}, respectively. The change in enthalpy for the reaction 3 C_{2} H_{2} (g) \to C_{6} H_{6} (1), is$ (1) $+ 324 kJ m o l^{- 1}$ (2) $+632 kJ m o l^{- 1}$ (3) $- 632 kJ m o l^{- 1}$ (4) $- 732 kJ m o l^{- 1}$ 270. $For the reaction given below the values of standard Gibbs free energy of formation at 298 K are given. What is the nature of the reaction? I_{2} + H_{2} S \to 2 H I + S ∆ G_{f}^{o} (H I) = 1.8 k J m o l^{- 1}, ∆ G_{f}^{o} (H_{2} S) = 33.8 k J m o l^{- 1}$ (1) $Non - spontaneous in forward direction$ (2) $Spontaneous in forward direction$ (3) $Spontaneous in backward direction$ (4) $Non - spontaneous in both forward and backward directions.$