Thermodynamics PYQs Set 11 (PDF)

Set 11 of 18 · Questions 301-330 of 511

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Mere Teacher · Previous Year Questions JEE Main Chemistry · Thermodynamics · Set 11 (Q301-330)
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301. $Given that, C (s) + O_{2} (g) ⟶ CO_{2} (g); Δ H^{\circ} = - x kJ mol^{- 1} 2 CO (g) + O_{2} (g) ⟶ 2 CO_{2} (g); Δ H^{\circ} = - y kJ mol^{- 1} The enthalpy of formation of CO will be$ (1) $\frac{y - 2 x}{3}$ (2) $\frac{y - 2 x}{2}$ (3) $\frac{2 x - y}{2}$ (4) $\frac{x - y}{2}$ 302. $Which of the followings is not a state function?$ (1) $Internal Energy$ (2) $Work$ (3) $Enthalpy$ (4) $Entropy$ 303. $Change in enthalpy for reaction, 2 H_{2} O_{2 (l)} \to 2 H_{2} O_{(l)} + O_{2 (g)} if heat of formation of H_{2} O_{2 (l)} and H_{2} O_{(l)} are - 188 and - 286 kJ/mol respectively, is$ (1) $- 196 kJ/mol$ (2) $+ 196 kJ/mol$ (3) $+ 948 kJ/mol$ (4) $- 948 kJ/mole$ 304. $Statement-1 : For every chemical reaction at equilibrium, standard Gibbs energy of reaction is zero. Statement-2 : At constant temperature and pressure, chemical reactions are spontaneous in the direction of decreasing Gibbs energy.$ (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) $Statement-1 is False, Statement-2 is True$ 305. $Considering the reaction : C_{(s)} + O_{2 (g)} \to CO_{2 (g)} + 393.5 kJ the signs of Δ H, Δ S and Δ G respectively are$ (1) $+,-,-$ (2) $-,+,+$ (3) $-,-,-$ (4) $-,+,-$ 306. $500 J of energy is transferred as heat to 0.5 mol of Argon gas at 298 K and 1.00 atm. The final temperature and the change in internal energy respectively are: Given : R = 8.3 J K^{- 1} m o l^{- 1}$ (1) $378 K and 500 J$ (2) $368 K and 500 J$ (3) $348 K and 300 J$ (4) $378 K and 300 J$ 307. $For the reversible reaction: A_{(s)} + B_{(g)} ⇌ C_{(g)} + D_{(g)} : Δ G^{\circ} = - 350 kJ . Which one of the following statements is true?$ (1) $The entropy change is negative.$ (2) $Equilibrium constant is greater than one.$ (3) $The reaction should be instantaneous.$ (4) $The reaction is thermodynamically not feasible.$ 308. $When two mole of an ideal gas heated from 300 K to 600 K at constant pressure. The change in entropy of gas (∆ S) is :$ (1) $\frac{3}{2} R ln 2$ (2) $-R \frac{3}{2} ln 2$ (3) $5R ln 2$ (4) $\frac{5}{2} R ln 2$ 309. $When one mole of an ideal gas is compressed to half of its initial volume and simultaneously heated to twice its initial temperature, the change in entropy of gas (∆ S) is :$ (1) $C_{p, m} ln 2$ (2) $C_{v, m} ln 2$ (3) $R ln 2$ (4) $(C_{v, m} - R) ln 2$ 310. $Consider the Born-Haber cycle for the formation of an ionic compound given below and identify the compound (Z) formed.$ (1) $MX$ (2) $M^{+} X_{(g)}^{-}$ (3) $M^{+} X$ (4) $none of these$ 311. $One mole of an ideal diatomic gas (Cv = 5 cal) was transformed from initial 2 5^{0} C and 1 L to the state when temperature is 10 0^{0} C and volume 10 L. Then for this process(R = 2 calories/mol/K) (take calories as unit of energy and kelvin for temp)$ (1) $∆ H = 525$ (2) $∆ S = 5 ln + 2 ln 10$ (3) $∆ E = 525$ (4) $∆ G of the process cannot be calculated using given information.$ 312. $Consider the given plot of enthalpy of the following reaction between A and B, A + B \to C + D Identify the incorrect statement$ (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) $Formation of A and B from C has highest enthalpy of activation.$ 313. $Total enthalpy change for freezing of 1 mol of water at 10^{\circ} C to ice at - 10^{\circ} C is . (Given: Δ_{fus} H = \frac{x kJ}{mol} C_{p} (H_{2} O (l)) = y J mol^{- 1} K^{- 1} C_{p} (H_{2} O (s)) = z J mol^{- 1} K^{- 1}$ (1) $- x - 10 y - 10 z$ (2) $x - 10 y - 10 z$ (3) $- 10 (100 x + y + z)$ (4) $10 (100 x + y + z)$ 314. $A certain mass of a gas was brought from state A to B by following three different paths, namely 1,2 and 3 respectively. Which of the following relations is correct for the work done?$ (1) $W_{1} = W_{2} = W_{3}$ (2) $W_{1} < W_{2} < W_{3}$ (3) $W_{1} > W_{2} > W_{3}$ (4) $W_{1} = W_{2} < W_{3}$ 315. $A reversible cyclic process for an ideal gas is shown below. Here, P, V, and T are pressure, volume and temperature, respectively. The thermodynamic parameters q, w, H and U are heat, work, enthalpy and internal energy, respectively. The correct option(s) is (are)$ (1) $qAC = ΔUBC and wAB = P2 (V2-V1)$ (2) $WBC = P2 (V2-V1) and qBC = ΔHAC$ (3) $ΔHCA < ΔUCA and qAC = ΔUBC$ (4) $qBC = ΔHAC and ΔHCA > ΔUCA$ 316. $For complete combustion of ethanol, C2H5OH(l) + 3 O_{2} (g) \to 2 C O_{2} (g) + 3H2O(l), the amount of heat produced as measured in bomb calorimeter, is 1364.47 kJ mol^{- 1} at 25°C. Assuming ideality the Enthalpy of combustion, ΔCH, for the reaction will be : (R = 8.314 J mol^{- 1})$ (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) $- 1350.50 kJ m o l^{-1}$ 317. $Given (A) 2CO(g)+ O_{2} (g) \to 2 C O_{2} (g) Δ H_{1}^{0} = -x kJ m o l^{- 1} (B) C(graphite)+ O_{2} (g) \to C O_{2} (g) Δ H_{2}^{0} = -y kJ m o l^{- 1} The ∆ H° for the reaction C (graphite)+ 12 O_{2} (g) \to CO(g) is$ (1) $\frac{2 x - y}{2}$ (2) $\frac{x + 2 y}{2}$ (3) $\frac{x - 2 y}{2}$ (4) $2y - x$ 318. $Two vessels A and B are connected via stopcock. The vessel A is filled with a gas at a certain pressure. The entire assembly is immersed in water and is allowed to come to thermal equilibrium with water. After opening the stopcock the gas from vessel A expands into vessel B and no change in temperature is observed in the thermometer. Which of the following statement is true?$ (1) $dq \neq = 0$ (2) $The pressure in the vessel B before opening the stopcock is zero$ (3) $dw \neq = 0$ (4) $dU \neq = 0$ 319. $At 25°C and 1 atm pressure, the enthalpy of combustion of benzene (1) and acetylene (g) are -3268 kJ m o l^{- 1} and -1300 kJ m o l^{- 1}, respectively. The change in enthalpy for the reaction 3 C_{2} H_{2} (g) \to C_{6} H_{6} (1), is$ (1) $+ 324 kJ m o l^{- 1}$ (2) $+632 kJ m o l^{- 1}$ (3) $- 632 kJ m o l^{- 1}$ (4) $- 732 kJ m o l^{- 1}$ 320. $For the reaction given below the values of standard Gibbs free energy of formation at 298 K are given. What is the nature of the reaction? I_{2} + H_{2} S \to 2 H I + S ∆ G_{f}^{o} (H I) = 1.8 k J m o l^{- 1}, ∆ G_{f}^{o} (H_{2} S) = 33.8 k J m o l^{- 1}$ (1) $Non - spontaneous in forward direction$ (2) $Spontaneous in forward direction$ (3) $Spontaneous in backward direction$ (4) $Non - spontaneous in both forward and backward directions.$ 321. $A sample of n -octane (1.14 g) was completely burnt in excess of oxygen in a bomb calorimeter, whose heat capacity is 5 kJ K^{- 1} . As a result of combustion reaction, the temperature of the calorimeter is increased by 5K. The magnitude of the heat of combustion of octane at constant volume is kJmol^{- 1} (nearest integer).$ 322. $One mole of an ideal monoatomic gas is subjected to changes as shown in the graph. The magnitude of the work done (by the system or on the system) is_______J (nearest integer). Given : log 2 = 03, In 10 = 23$ 323. $The value of log K for the reaction A ⇌ B at 298 K is________. (Nearest integer) Given: Δ H^{0} = -54.07 kJ mol-1 Δ S^{0} = 10 JK^{- 1} mol-1 (Taken 2.303 x 8.314 x 298 = 5705)$ 324. $Data given for the following reaction is as follows: F e O_{(s)} + C_{(g r a p hi t e)} ⟶ F e_{(s)} + C O_{(g)} The minimum temperature in at which the reaction becomes spontaneous is ____. (Integer answer)$ 325. $For water Δ_{v a p} H = 41 kJ mol-1at 373 K and bar pressure. Assuming that water vapour is an ideal gas thatoccupies a much larger volume than liquid water, the internal energy change during evaporation of water is____kJmol^{- 1} [Use : R = 8.3 J mol-1 K^{- 1}]$ 326. $For the reaction \frac{1}{2} N2(g) + \frac{3}{2} H2(g) \to NH3(g) ; ΔH = - 30 kJ to be at equilibrium at 477ºC. If standard entropy of N2 (g) and NH3 (g) are 60 and 50 J mole^{-1} K^{-1} respectively then calculate the standard entropy of H2(g) in Jmole^{-1} K^{-1} .$ 327. $For complete combustion of methanol C H_{3} O H (l) + \frac{3}{2} O_{2} (g) \to C O_{2} (g) + 2 H_{2} O (l) the amount of heat produced as measured by bomb calorimeter is 726 kJ m o l^{- 1} at 27°C. The enthalpy of combustion for the reaction is -x kJ m o l^{- 1}, where x is______. (Nearest integer)(Given :R = 8.3 J K^{- 1} m o l^{- 1})$ 328. $An ideal gas undergoes a cyclic transformation starting from the point A and coming back to the same point by tracing the path A \to B \to C \to A as shown in the diagram. The total work done in the process is______J .$ 329. $A fish swimming in water body when taken out from the water body is covered with a film of water of weight 36 g. When it is subjected to cooking at 100°C, then the internal energy for vaporization in kJ m o l^{- 1} is ________. [nearest integer] [Assume steam to be an ideal gas. Given for water at 373 K and 1 bar is 41.1 kJ m o l^{- 1}; R = 8.31 J K^{- 1} m o l^{- 1}]$ 330. $What happens when methane undergoes combustion in systems A and B respectively? (a) System A System B Temperature rises Temperature remains same (b) System A System B Temperature remains same Temperature rises (c) System A System B Temperature falls Temperature remains same (d) System A System B Temperature falls Temperature rises$