# CBSE Questions for Class 11 Medical Chemistry Thermodynamics Quiz 13 - MCQExams.com

 The value of $$\triangle G$$ for the process $$H_{2}O(s) \rightarrow H_{2}O(l)$$ at $$1\ atm$$ and $$260\ K$$ is:-
• $$< 0$$
• $$= 0$$
• $$> 0$$
• Unpredictable
 Statement I: In adsorption process, the value of $$\Delta H$$ is always negative.Statement II: During adsorption surface area of adsorbent decreases.Which of the above statement is/are true? Choose the correct option.
• Only I
• Only II
• I and II
• None of these
 Following reaction occurs at $${25}^{o}C$$:$$2NO(g, 1\times { 10 }^{ -5 }atm)+{ Cl }_{ 2 }(g, 1\times { 10 }^{ -2 }atm)\rightleftharpoons 2NOCl\ \left( g, 1\times { 10 }^{ -2 }atm \right)$$$$\Delta { G }^{ o }$$ is_______________.
• $$-45.65kJ$$
• $$-28.53kJ$$
• $$-22.82kJ$$
• $$-57.06kJ$$
 For the process $${ H }_{ 2 }O(1,1bar,373.15k)\rightarrow { H }_{ 2 }O(g,1bar,373.15k)$$, the correct set of thermodynamic parameters is:
• $$\Delta G\ =\ 0,\ \Delta S\ =\ +\ ve$$
• $$\Delta G\ =\ 0,\ \Delta S\ =\ -ve$$
• $$\Delta G\ =\ +ve,\ \Delta S\ =\ 0$$
• $$\Delta G\ =\ -ve,\ \Delta S\ =\ +ve$$
 When two moles of Hydrogen atoms join together to form a mole of hydrogen molecules in closed rigid vessel with diathermic walls:$$H(g)+H(g)\longrightarrow { H }_{ 2 }(g)$$
• $$w< 0$$
• $$\Delta U=negative$$
• $${ q }_{ system }=positive\quad$$
• $${ q }_{ surrounding }=negative\quad$$
 The difference between the heat of reaction at constant pressure and constant volume for the reaction given below at $${25}^{o}C$$ in KJ is: $$\quad 2{ C }_{ 6 }{ H }_{ 6(l) }+15{ O }_{ 2(g) }\longrightarrow 12{ CO }_{ 2(g) }+6{ H }_{ 2 }{ O }_{ (l) }$$
• $$-7.43$$
• $$+3.72$$
• $$-3.72$$
• $$+7.43$$
 For reversible isothermal expansion of one mole of an ideal gas at $$300 K$$, from a volume of $$10 L$$ to $$20 L$$, $$\Delta H$$ is :
• $$1.73 kJ$$
• $$-1.73 kJ$$
• $$3.46 kJ$$
• zero
 The normal boiling point of a liquid A is 350 K. $$\Delta { H }_{ vap }$$ at normal boiling point is 35 KJ/mole. Pick out the correct statement(s). (Assume $$\Delta { H }_{ vap }$$ to be independent of pressure).
• $$\Delta { S }_{ vaporisation }$$ > 100 J/K mole at 350 K and 0.5 atm
• $$\Delta { S }_{ vaporisation }$$ < 100 J/K mole at 350 K and 0.5 atm
• $$\Delta { S }_{ vaporisation }$$ < 100 J/K mole at 350 K and 2 atm
• $$\Delta { S }_{ vaporisation }$$ = 100 J/K mole at 350 K and 2 atm
 Mayuri was performing thermometric titration and she took 100 ml of $$1 M$$ sulphuric acid and started adding $$1 M$$ calcium hydroxide. When she plotted a graph of temperature vs volume of the titrant added, she found that the temperature was initially increasing and then it started decreasing. The maximum of the graph is obtained at 100 ml of calcium hydroxide. What will be the enthalpy change of this reaction?[Given: $$\Delta H\ = -13.7 kcal/eq$$]
• -13.7 kcal
• -27.4 kcal
• -1.37 kcal
• -2.74 kcal
 The lattice energy of $$CsI(s)$$ and the enthalpy of solution is $$33\ kJ/mol$$. Calculate the enthalpy of hydration $$(kJ)$$ of 0.65 moles of $$CsI$$.
• $$738 kJ$$
• $$10 kJ$$
• $$-371 kJ$$
• $$-822 kJ$$
 The heat liberated on complete combustion of 1 mole of $${ CH }_{ 4 }$$ gas to $${ CO }_{ 2 }\left( g \right)$$ and $${ HO }_{ 2 }\left( l \right)$$ is 890 KJ. Calculate the heat evolved by 2.4 L of $${ CH }_{ 4 }$$ on complete combustion.
• 95.3 KJ
• 8900 KJ
• 89 KJ
• 8.9 KJ
 For the reaction, $${ X }_{ 2 }{ O }_{ 4 }\left( l \right) \longrightarrow 2X{ O }_{ 2 }\left( g \right)$$$$\Delta U=2.1\ k\ cal$$, $$\Delta S=20\ cal\ { K }^{ -1 }$$ at 300 K Hence , $$\Delta G$$ is_________.
• +2.7 kcal
• -2.7 kcal
• +9.3 kcal
• -9.3 kcal
 The value of $$\Delta G$$ for the process $${ H }_{ 2 }O\left( s \right) \rightarrow { H }_{ 2 }O\left( l \right)$$  at 1 atm and 260 K is:
• <0
• =0
• >0
• unpredictable
 For an ideal gas $$\displaystyle \frac {C{p,m}}{C{v,m}}\,=\,\gamma$$. The molecular mass of the gas is M , its specific heat capacity at constant volume is:
• $$\displaystyle \frac{R}{M(\gamma\,-\,1)}$$
• $$\displaystyle \frac{M}{R(\gamma\,-\,1)}$$
• $$\displaystyle \frac{\gamma\,RM}{\gamma\,-\,1}$$
• $$\displaystyle \frac{\gamma R}{M(\gamma\,-\,1)}$$
 For the reversible isothermal expansion of one mole of an ideal gas at $$300$$ $$K$$, from a volume of $$10 L$$ to $$20 L$$, $$\Delta H$$ is :
• $$1.73 \ kJ$$
• $$-1.73 \ kJ$$
• $$3.46 \ kJ$$
• 0
 Consider the following process$$\Delta H(kJ/mol)$$$$\frac{1}{2}A\rightarrow B +50$$$$3B \rightarrow 3C +D -125$$$$E + A \rightarrow 2D + 350$$For $$B + D \rightarrow E +2C, \Delta H$$will be:
• 325 kJ/mol
• 525 kJ/mol
• -375 kJ/mol
• -325 kJ/mol
 It for reaction $$N_2(g)+3H_2(g) \rightarrow 2NH_2(g), \Delta H_{1}^{0}=-30$$KJ/mole at temprature $$300$$ K and it specific heat capacities of different species are $$S_{P,N_{2}}=1J/g^{0}C$$ and $$S_{P,NH_{2}}=j/g^{0}C$$, then $$\Delta H_{2}^{0}$$ at $$400$$ K for the same reaction will be (assume heat capacities to be constant in given temperature range)
• $$-32 k j/$$mole
• $$-28 k J/$$mole
• $$-32.7 kJ/$$mole
• $$-27.3 kJ/$$mole
 $${ NH }_{ 2 }{ CN }_{ \left( s \right) }+\dfrac { 3 }{ 2 } { O }_{ 2\left( g \right) }\rightarrow { N }_{ 2\left( g \right) }+{ CO }_{ 2\left( g \right) }+{ H }_{ 2 }{ O }_{ \left( l \right) }$$This reaction is carried out in a bomb calorie-meter. The heat released was $$743\ KJ\ { mol }^{ -1 }$$. The value of $${ \Delta H }_{ 300 }$$ for this reaction would be:
• $$-740\ KJ\ { mol }^{ -1 }$$
• $$-741.75\ KJ\ { mol }^{ -1 }$$
• $$-743.0\ KJ\ { mol }^{ -1 }$$
• $$-744.25\ KJ\ { mol }^{ -1 }$$
 The three thermodynamic states $$P, Q$$ and $$R$$ of a system are connected by the paths shown in the figure given on the right. The entropy change in the processes $$P \rightarrow Q , Q \rightarrow R$$ and $$P\rightarrow R$$ along the paths indicated are $$\triangle S_{P Q}, \triangle S_{QR}$$ and $$\triangle S_{PR}$$ respectively. If the process $$P \rightarrow Q$$ is adiabatic and irreversible, while $$P\rightarrow R$$ is adiabatic and reversible, the correct statement is:
• $$\triangle S_{QR} > 0$$
• $$\triangle S_{PR} > 0$$
• $$\triangle S_{QR} < 0$$
• $$\triangle S_{PQ} > 0$$
Given the following data:
 Substrate $$\Delta H^o$$(kJ/mol) $$S^o$$(J/mol K) $$\Delta G^o$$ (kJ/mol) FeO(s) $$-266.3$$ $$57.49$$ $$245.12$$ C(Graphite) $$0$$ $$5.74$$ $$0$$ Fe(s) $$0$$ $$27.28$$ $$0$$ CO(g) $$-110.5$$ $$197.6$$ $$-137.15$$
Determine at what temperature the following reaction spontaneous?
$$FeO(s)+C(Graphite)\rightarrow Fe(s)+CO(g)$$
• $$298$$ K
• $$668$$ K
• $$966$$ K
• $$\Delta G^o$$ is $$+$$ve, hence the reaction will never be spontaneous
 If the bond dissociation energies of $$XY$$, $${ X }_{ 2 }$$ and $${ Y }_{ 2 }$$ (all diatomic molecules) are in the ratio of $$1:1:0.5$$ and $${ \Delta }_{ 1 }H$$ for the formation of XY is $$-200\ kJ\ { mol }^{ -1 }$$. The bond dissociates energy of $${ X }_{ 2 }$$ will be:
• $$100\ kJ\ mol^{-1}$$`
• $$200\ kJ\ mol^{-1}$$
• $$800\ kJ\ mol^{-1}$$
• $$400\ kJ\ mol^{-1}$$
 For the reaction at $$25, X_{ 2 }O_{ 4 } { O }_{ 4_{ (l) } } \longrightarrow 2X { O }_{ 2_{ (g) } }$$.$$\Delta H =$$2.1 kcal and $$\Delta S =$$20 cal $${ K }^{ -1 }$$. The reaction would be:
• spontaneous
• non-spontaneous
• at equilibrium
• unpredictable
 When a block of iron floats in mercury at $$0^o$$C, a fraction $$k_1$$ of its volume is submerged, while at the temperature $$60^o$$C, a fraction $$k_2$$ is seen to be submerged. If the coefficient of volume expansion of iron is $$\gamma _{Fe}$$ and that of mercury is $$\gamma_{Hg}$$, then the ratio $$k_1/k_2$$ can be expressed as.
• $$\dfrac{1+60\gamma_{Fe}}{1+60\gamma_{Hg}}$$
• $$\dfrac{1-60\gamma_{Fe}}{1+60\gamma_{Hg}}$$
• $$\dfrac{1+60\gamma_{Fe}}{1-60\gamma_{Hg}}$$
• $$\dfrac{1+60\gamma_{Hg}}{1+60\gamma_{Fe}}$$
 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?$$I_2 + H_2S \rightarrow 2HI + S$$$$\Delta G_f^0 (HI) = 1.8 \ kJ\ mol^{-1}$$, $$\Delta G_f^0 (H_2S) = 33.8 \ kJ\ mol^{-1}$$
• Non-spontaneous in forward direction
• Spontaneous in forward direction
• Spontaneous in backward direction
• Non-spontaneous in both forward and backward directions
 What will be $$\Delta G$$ for the reaction at $$25^0C$$ when partial pressures of reactants $$H_2$$, $$CO_2$$, $$H_2O$$ and $$CO$$ are 10, 20, 0.02 and 0.01 atm respectively?[Given : $$G^0_{H_2O}$$ $$= -228.58$$ kJ,  $$G^0_{CO}$$ $$= - 137.15$$ kJ and $$G^0_{CO_2}$$ $$= -394.37$$ kJ.]
• +5.61 kJ
• -5.61 kJ
• 7.09 kJ
• -8.13 kJ
 Which of the following statements is correct for a reverse process in a state of equilibrium ?
• $$\Delta G=2.30\quad RT\quad log\quad K$$
• $$\Delta { G }^{ o }=-2.30\quad RT\quad log\quad K$$
• $$\Delta { G }^{ o }=2.30\quad RT\quad log\quad K$$
• $$\Delta { G }=-2.30\quad RT\quad log\quad K$$
 Which thermochemical law is represented by the following figure?
• Standard enthalpy of a reaction
• Born - Haber cycle of lattice enthalpy
• Hess's law of constant heat summation
• Standard enthalpy of a solution
 $$\Delta S$$ will be highest for the reaction:
• $$2Ca(s)+O_2(g) \rightarrow 2CaO(s)$$
• $$CaCO_3(s) \rightarrow CaO(s) +CO_2(g)$$
• $$C(s)+O_2(g)\rightarrow CO_2(g)$$
• $$N_2(g)+O_2(g)\rightarrow 2NO(g)$$
 In which of the following pair of reactions first reaction is spontaneous while second reaction is non spontaneous?
• (i) $$^{-}SH+H_2O\rightarrow H_2S+OH^-$$

(ii) $$NH^-_2+H_2O\rightarrow NH_3+OH^-$$
• (i) $$^{-}OR+H_2SO_4\rightarrow ROH+HSO^-_4$$

(ii) $$R^-+NH_3\rightarrow RH+NH^-_2$$
• (i) $$Cl^{-}+HF\rightarrow HCl+F^-$$

(ii) $$^-OH+HCl\rightarrow H_2O+Cl^-$$
• (i) $$^-OH+HBr\rightarrow H_2O+Br^-$$

(ii) $$RO^-+NH_3\rightarrow ROH+NH^-_2$$
 If $$\Delta H> 0$$ and $$\Delta S> 0$$, the reaction proceeds spontaneously when:
• $$\Delta H > T \Delta S$$
• $$\Delta H < T \Delta S$$
• $$\Delta H=T\Delta S$$
• $$None\ of\ the\ above$$
 Which of the following conditions regarding a chemical process ensures its spontanlity at all temperature?
• $$\triangle H>0,\quad \triangle G<0$$
• $$\triangle H<0,\quad \triangle S>0$$
• $$\triangle H<0,\quad \triangle S<0$$
• $$\triangle H>0,\quad \triangle S<0$$
 In a constant volume calorimeter, 5 g of gas with molecular weight 40 was burnt in excess of oxygen at 298 K. The temperature of the calorimeter was found to increase from 298 K to 298.75 K due to the combustion process. Given that the heat capacity of the calorimeter is 2.5 kJ$${ K }^{ -1 }$$, the numerical value for the $$\triangle U$$ of combustion of the gas in kJ $${ mol }^{ -1 }$$ is:
• 15
• 12
• 90
• 8
 For which reaction will $$\Delta H=\Delta U$$ ?
• $$H_2(g)+Br_2(g)\rightarrow 2HBr(g)$$
• $$C(s)+2H_2O(g)\rightarrow 2H_2(g)+CO_2(g)$$
• $$PCl_5(g)\rightarrow PCl_3(g)+Cl_2(g)$$
• $$2CO(g)+O_2(g)\rightarrow 2CO_2(g)$$
 A system is taken along paths A and B as shown. If amounts of heat given in these processes are respectively QA and QB, then:
• QA=QB
• QA>QB
• $$QB<QA$$
• none of these
 For a particular reaction $$\triangle H^0 = -76.6 KJ$$ and $$\Delta S^0 = 226 JK^{-1}$$. This reaction is:
• spontaneous at all temperatures
• non-spontaneous at all temperatures
• spontaneous at temperature below $$66^0$$C
• spontaneous at temperature above $$66^0$$C
Given the following data:
 Substance $$\Delta H^{o}(kJ/mol)$$ $$\Delta S^{o}(kJ/mol)$$ $$\Delta G^{o}(kJ/mol)$$ $$FeO(s)$$ $$-266.3$$ $$57.49$$ $$-245.12$$ $$C$$(Graphite) $$0$$ $$5.74$$ $$0$$ $$Fe(s)$$ $$0$$ $$27.28$$ $$0$$ $$CO(g)$$ $$-110.5$$ $$197.6$$ $$-137.15$$
Determine at what temperature the following reaction is spontaneous?
$$FeO(s)+C(Graphite)\rightarrow Fe(s)+CO(g)$$
• $$298\ K$$
• $$668\ K$$
• $$966\ K$$
• $$\Delta G^{o}$$ is +ve the reaction will never be spontaneous
 For the following concentration cell,to be spontaneous $$Pt({H}_{2}){P}_{1} atm |HCl\ || \ Pt({H}_{2}), {P}_{2} atm$$.Which of the following is correct?
• $${P}_{1}={P}_{2}$$
• $${P}_{1}<{P}_{2}$$
• $${P}_{1}>{P}_{2}$$
• Can't be predicted
Given the following data:
 Substance $$\triangle H^0 (kJ/mol)$$ $$S^0 (J/molK)$$ $$\triangle G^0(kJ/mol)$$ FeO(s) $$-266.3$$ $$57.49$$ $$-245.12$$ C(Graphite) 0 $$5.74$$ 0 Fe(s) 0 $$27.28$$ 0 CO(g) $$-110.5$$ $$197.6$$ $$-137.15$$

Determine at what temperature the following reaction is spontaneous?
$$FeO(s) + C(Graphite) \rightarrow Fe(s) + CO(g)$$
• $$298$$K
• $$668$$K
• $$966$$K
• $$\triangle G^0$$ is +ve, hence the reaction will never be spontaneous.
 Consider the following reactions. In which case the formation of product is favoured by decrease in pressure?(1) $$CO_2(g)+C(s) \rightarrow 2CO(g)$$; $$\Delta H=+172.5$$ kJ(2) $$N_2(g)+3H_2(g) \rightarrow 2NH_3(g)$$; $$\Delta H=-91.8$$ kJ(3) $$N_2(g)+O_2(g) \rightarrow 2NO(g)$$; $$\Delta H=+181$$ kJ(4) $$2H_2O(g) \rightarrow 2H_2(g)+O_2(g); \Delta H=484.6$$ kJ
• 2,3
• 3,4
• 2,4
• 1,4
 Standard entropy of $${X}_{2},{Y}_{2}$$ and $$X{Y}_{3}$$ are $$60,40$$ and $$50$$ $$J{K}^{-1}$$ $${mol}^{-1}$$, respectively. For the reaction,$$\cfrac{1}{2}{X}_{2}+\cfrac{3}{2}{Y}_{2}\rightarrow {XY}_{3}.\Delta H=-30kJ$$ to be at equilirbium, the temperature will be:
• $$1250K$$
• $$500K$$
• $$750K$$
• $$1000K$$
 Pressure of $$10$$ moles of an ideal gas is changed from $$2\ atm$$ to $$1\ atm$$ against constant external pressure without change in temperature. If surrounding temperature ($$300\ K$$) and pressure ($$1\ atm$$) always remains constant then calculate total entropy change ($$\Delta {S}_{system}+\Delta {S}_{surrounding}$$) for given process.[Given: $$\ln{2}=0;70$$ and $$R=8.0J/mol/K$$]
• $$56J/K$$
• $$14J/K$$
• $$16J/K$$
• None of these
 The change in entropy of $$2$$ moles of an ideal gas upon isothermal expansion at $$243.6K$$ from $$20$$ litre until the pressure becomes $$1atm$$ is:
• $$1.385\ cal/K$$
• $$-1.2\ cal/K$$
• $$1.2\ cal/K$$
• $$2.77\ cal/K$$
 Two samples of DNA, A and B have melting points $$340K$$ and $$350K$$ respectively. This is because
• B has more GC content than A
• A has more GC content than B
• B has more AT cotent than A
• both have same AT content
 If $$\Delta {H}_{vaporisation}$$ of substance $$X(l)$$ (molar mass :$$30g/mol$$) is $$300J/g$$ at its boiling point $$300K$$, then molar entropy change for reversible condensation process is:
• $$30J/mol.K$$
• $$-300J/mol.K$$
• $$-30J/mol.K$$
• None of these
 In conversion of line-stone to lime,$$Ca{CO}_{3}(s)\rightarrow CaO(s)+{CO}_{2}(g)$$the values of $$\Delta {H}^{o}$$ and $$\Delta {S}^{o}$$ are $$+179.1kJ{mol}^{-1}$$ and $$160.2J/K$$ respectively at $$298K$$ and $$1$$ bar. Assuming that $$\Delta {H}^{o}$$ and $$\Delta {S}^{o}$$ do not change with temperature, temperature above which conversion of limestone to lime will be spontaneous is:
• $$1008K$$
• $$1200K$$
• $$845K$$
• $$1118K$$
 Which of the following statements/relationships is not correct in thermodynamic changes?
• $$w=-nRT\ln{\cfrac{{V}_{2}}{{V}_{1}}}$$ (isothermal reversible expansion of an ideal gas)
• For a system at constant volume, heat involved is equal to change in internal energy.
• $$w=nRT\ln{\cfrac{{V}_{2}}{{V}_{1}}}$$ (isothemal reversible expansion of an ideal gas)
• $$\Delta U=0$$ (isothermal reversible expansion of an ideal gas)
 An intimate of ferric oxide $$({Fe}_{2}{O}_{3})$$ and aluminum (Al) is used as solid rocket fuel. Calculate fuel value per gram of the mixture Heats of formation are as follows: $$\triangle { H }_{ f }\left( { Al }_{ 2 }{ O }_{ 3 } \right) =399\quad kcal/mole$$$$\triangle { H }_{ f }\left( { Fe }_{ 2 }{ O }_{ 3 } \right) =199\quad kcal/mole$$
• $$0.9345 Kcal/g$$
• $$200 Kcal/g$$
• $$3.94Kcal/g$$
• None
 Ethyl chloride ($${C}_{2}{H}_{5}Cl$$), is prepared by reaction of ethylene with hydrogen chloride:$${C}_{2}{H}_{4}(g)+HCl(g)\rightarrow {C}_{2}{H}_{5}Cl(g)$$$$\Delta {H}=-72.3kJ/mol$$What is the value of $$\Delta {E}$$ (in kJ), if $$70g$$ of ethylene and $$73g$$ of $$HCl$$ are allowed to react to $$300K$$
• $$-69.8$$
• $$-180.75$$
• $$-174.5$$
• $$-139.6$$
 Assuming that water vapour is an ideal gas, the internal energy change ($$\Delta U$$) when $$1mol$$ of water is vaporised at $$1$$ bar pressure and $${100}^{o}C$$ will be:(Given: Molar enthalpy of vapourisation of water at $$1$$ bar and $$373K=41\ kJ.{mol}^{-1}$$ and $$R=8.3J{mol}^{-1}$$ $${K}^{-1}$$)
• $$4.100\ kJ$$ $${mol}^{-1}$$
• $$3.7904\ kJ$$ $${mol}^{-1}$$
• $$37.904\ kJ$$ $${mol}^{-1}$$
• $$41.00\ kJ$$ $${mol}^{-1}$$
 Heat of reaction for, $$CO(g)+\dfrac{1}{2}{O}_{2}(g)\rightarrow {CO}_{2}(g)$$ at constant $$V$$ is $$-67.71Kcal$$ at $${17}^{o}C$$. The heat of reaction at constant $$P$$ at $${7}^{o}C$$ is :
• $$-68.0KCal$$
• $$+68.0KCal$$
• $$-67.42Kcal$$
• None