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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 2701. |
The standard heat of combustion of a solid boron is equal to:A. `DeltaH_(f)^(@)(B_(2)O_(3))`B. `1//2DeltaH_(f)^(@)(B_(2)O_(3))`C. `2DeltaH_(f)^(@)(B_(2)O_(3))`D. `1//2DeltaH_(f)^(@)(B_(2)O_(3))` |
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Answer» Correct Answer - B Combustion reaction of solid boron `B(s)+(3)/(4)O_(2)(g)rarr(1)/(2)B_(2)O_(3)(s)` `Delta H_(r )^(o)=Delta H_(c )^(o)=(1)/(2)DeltaH_(f)^(o)(B_(2)O_(3),s)-Delta H_(f)^(o)(B,s)-(3)/(4)Delta H_(f)^(o)(O_(2),g)` `Delta H_(f)^(o)` of element in stable state of aggregation is assumed to be zero. `DeltaH_(c )^(@)=(1)/(2)Delta H_(f)^(o)(B_(2)O_(3),s)` |
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| 2702. |
isotherm is aA. P-V curve at constant temperatureB. P-T curve at constant volumeC. V-T curve at constant pressureD. P-V at constant internal energy |
| Answer» Correct Answer - A | |
| 2703. |
Which of the following is not a path function ?A. `DeltaQ`B. `DeltaQ+DeltaW`C. `DeltaW`D. `DeltaQ-DeltaW` |
| Answer» Correct Answer - D | |
| 2704. |
When reaction is at standard state at equilibrium, thenA. `DeltaH^(@)=0`B. `DeltaS^(@)=0`C. `"equillibrium constant" K=0`D. `"equillibrium constant" K=1` |
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Answer» Correct Answer - D |
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| 2705. |
The standard heat of combustion of solid boron is equal to :A. `DeltaH_(f)^(@)(B_(2)O_(3))`B. `(1)/(2)DeltaH_(f)^(@)(B_(2)O_(3))`C. `2DeltaH_(f)^(@)(B_(2)O_(3))`D. `(1)/(4)DeltaH_(f)^(@)(B_(2)O_(3))` |
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Answer» Correct Answer - B |
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| 2706. |
For the gas-phase decomposition, `PCl_(5)(g)LeftrightarrowPCl_(3)(g)+Cl_(2)(g)`A. `DeltaH lt DeltaSlt0`B. `DeltaH gt DeltaSgt0`C. `DeltaH gt DeltaSlt0`D. `DeltaH lt DeltaSgt0` |
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Answer» Correct Answer - B |
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| 2707. |
What is the property of a system or a system variable ? |
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Answer» The property of a system or a system variable is any measurable or observable characteristic or property of the system when the system remains in equilibrium. |
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| 2708. |
2 mole of zinc is dissolved in HCl at `25^(@)` C. The work done in open vessel is :A. `-2.477 kJ`B. `-4.955 kJ`C. 0.0489 kJD. None of these |
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Answer» Correct Answer - B |
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| 2709. |
From the following data of `DeltaH`, of the following reactions `C(s)+(1)/(2)O_(2)(g)toCO(g)" "DeltaH=-110kJ` `C(s)+H_(2)O(g)toCO(g)+H_(2)(g)" "DeltaH=132kJ` What is the mole composition of the mixture of steam and oxygen on passed over coke at 1273 K, to maintain constant temperature :A. `0.5 : 1`B. `0.6 : 1`C. `0.8 : 1`D. `1 : 1` |
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Answer» Correct Answer - B |
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| 2710. |
Name the macroscopic variables of a system. |
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Answer» Pressure, volume, temperature, density, mass, specific volume, amount of substance (expressed in mole) are macroscopic variables of a system. Notes : The quantities specified above are not totally independent, e.g., 1. density = mass/volume 2. specific volume (volume per unit mass) = 1/density. |
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| 2711. |
Calculate `log_(10){[C]_(eq)//[A]_(eq)}` where [C] and [A] are equilirium molar concetration of respective species, when 2 2 mole each of A and B were allowed to come to equilibrium at 900 K. `A + B overset(900 K) hArrC + D" ", " "DeltaG^(@) = 460.6 "Calorie"` Take: `underset(R=2 Cal //K"mole")(ln X = 2.303 log X)`A. `5.56 xx 10^(-02)`B. `5.57 xx 10^(-03)`C. `1.1 xx 10^(-2)`D. `1.1 xx 10^(-3)` |
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Answer» Correct Answer - A `DeltaG^(@)= 2.303 RT log K_(C)` `460.6 = - 2.303 xx 2 xx 900 log K_(C)` `log K_(C) = -(1)/(9)` `log .([C]_(eq)^(2))/([A]_(eq)^(2))=(1)/(9)" "log.([C]_(eq))/([A]_(eq)) = -(1)/(18) = 5.56 xx 10 ^(2) " "("at equilibrium "[C]_(eq) = [D]_(eq)[A]_(eq)=[B]_(eq))` |
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| 2712. |
What is the free energy change `(DeltaG)` when `1.0 "mole"` of water at `100^(@)C` and atm pressure is converted into steam at `100^(@)C` and 1 atm pressure?A. 80 calB. 540 calC. 620 calD. zero |
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Answer» Correct Answer - D |
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| 2713. |
What is an intensive variable ? Give examples. |
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Answer» A variable that does not depend on the size of the system is called an intensive variable. Examples : pressure, temperature, density. |
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| 2714. |
What is mechanical equilibrium ? |
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Answer» A system is said to be in mechanical equilibrium when there are no unbalanced forces within the system and between the system and its surroundings. OR A system is said to be in mechanical equilibrium when the pressure in the system is the same throughout and does not change with time. [Note : The constituents of a system, atoms, molecules, ions, etc, are never at rest. Within a system, even in the condition of equilibrium, statistical fluctuations do occur, but the time of observation is usually very large so that these fluctuations can be ignored.] |
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| 2715. |
Which of the followig is extensive variable?A. Internal energyB. TemperatureC. PressureD. Density |
| Answer» Correct Answer - A | |
| 2716. |
What is an extensive variable ? Give examples. |
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Answer» A variable that depends on the size of the system is called an extensive variable. Examples : internal energy, mass. |
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| 2717. |
What is the free energy charge `(DeltaG)` when 1.0 mole of water at `100^(@)C` and 1 atm pressure is converted into steam at ` 100^(@)C` and 1 atm pressure ?A. 80 calB. 540 calC. 620 calD. zero |
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Answer» Correct Answer - D `DeltaG^(@)` = 0 at equilibrium |
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| 2718. |
An ideal gas `(C_(P)//C_(V)=gamma)` is expanded so that the amount of heat transferred to the gas the is equal to the decrease in its internal energy . What is the molar heat capacity of gas in this process ?A. `C_(V)`B. `-C_(V)`C. `C_(P)`D. `2C_(V)` |
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Answer» Correct Answer - B `dq = - dU` `n. C dT = - n C_(v)dT` `thereforeC=- C_(V)` |
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| 2719. |
An ideal gas `(C_(P)//C_(V)=gamma)` is expanded so that the amount of heat transferred to the gas the is equal to the decrease in its internal energy . What is the relationship between temperature and volume of gas in this process ?A. `T. V^(2(gamma-1))= "constant"`B. `T. V^(gamma-1)= "constant"`C. `T. V^((gamma-1//2))= "constant"`D. `T. V^(gamma)= "constant"` |
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Answer» Correct Answer - C `dq = dU +p dV` `- dU = dU + pdV` `- 2n C_(V)dT=(nRT)/(V) d V` `int(dT)/(T)= (R)/(2C_(V))int(dV)/(V)+ "constant"` `therefore T V ^(gamma-1)="constant"` |
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| 2720. |
Calculate the final pressure of a sample of carbon dioxide that expands reversibly and adiabatically from `57.4kPa` and `1.0` to a final volume of `2.0L` . Take `gamma = 1.4` |
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Answer» Correct Answer - 22 |
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| 2721. |
An ideal gas is expanded so that the amount of heat transferred to the gas is equal to the double the decrease in enthalpy . Indentify the options which are correct .[Symbols have usual meaning ]A. `PV^((3gamma)/(2gamma+1))`= constantB. Molar heat cacity =`2C_(p)`C. `TV^((gamma-1)/(2gamma+1))`= constantD. `P^(1-gamma)T^(gamma)`=constant |
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Answer» Correct Answer - a,c |
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| 2722. |
In how many of the folowinf reaction `|H^(@)|gt|DeltaE^(@)|`, assuming reacftion to be occurring at a constant temperature and pressure. `H_(2)+(1)/(2)O_(2)rarrH_(2)O(l)` Combustion of `C_(2)H_(8)(g)` at 400 K Dimerisation of `NO_(2)(g)` Fusion of water at `0^(@)` C Vaporisation of any liquid at its boiling poing Dossociation of `CaCO_(3)(s)` Combustion of `C_(2)H_(4)` at 300m K |
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Answer» Correct Answer - 5 |
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| 2723. |
3 moles of an ideal gas`(gamma=5//3)` is subjected to following charge of state . Identify the correct statement : satete A(400 K, 2 bar) `underset ("isothermal cooling") overset("Reversible")to ` state B `(T_(B),T_(B)) underset ("isothermal expansion") overset("Reversible")to State C` `(300 K, 1 "bar")underset("free expansion") overset("Asiabatic")to State D (T_(D), 0.5 "bar")`A. `T_(B)` and `T_(D)` will be same and equal to 300 KB. `DeltaH_(AD)=750 R`C. `DeltaS_(AC)=0`D. `DeltaE_(BD)=0` |
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Answer» Correct Answer - a,d |
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| 2724. |
Calculated the final temprature (in Kelvin of a sample of argon of mass 12.0 g that is expanjded reversibly and adiabatically from 1.0 L at at 273 K to 3.0 L. (Take :`3sqrt9=2.08`) |
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Answer» Correct Answer - 131 |
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| 2725. |
Which of the following process must be spontaneous ?A. Isobaric and isoentropic process with negative enthalpy charge.B. Isobaric and isoentropic process with negative internal energy change .C. A process with constant internal energy and isothermal with an increase in entropy of systemD. An adiabatic process with constant volume consition and entropy of system increasing . |
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Answer» Correct Answer - a,d |
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| 2726. |
Entropy of a perfect crystalline solid at absolute zero isA. ZeroB. Less than zeroC. Greater than zeroD. Depends upon nature of the solid |
| Answer» Correct Answer - A | |
| 2727. |
A picece of zinc of mass 5.0 g is dropped into a beaker of dilute hydrochloric acid. Calculate the work done by the system (mangnitude only in J) as a result of the reaction. The atmospheric pressure is 1.1 atm and temperture `23^(@)` C. |
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Answer» Correct Answer - 189 |
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| 2728. |
In the thermite reaction used for obtaining energy, aluminium and ferric oxide react to from iron and aluminium oxide . From the given datw identify the option (s) which is (are ) correct : [Given :`Delta H_(f)^(@) Al_(2)O_(3) =- 390 KJ//"mole"`, `DeltaH_(f)^(@) Fe_(2)O_(3)=-176kJ//mol`, density of aliuminium `=2.7gm//ml` density of `Fe_(2)O_(3)=-3.2gm//ml"]`A. Maximum calorific value of the fuel can be `1000 J//gm.`B. Maximum calorific vale of the fuel can be `(21.4)/(7) kJ//ml`.C. `2.14 kg` of the mixture can produce 2500 kJ of heat .D. `140 ml ` of the mixture can produce 280 kJ of heat . |
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Answer» Correct Answer - a,b,d |
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| 2729. |
Which of the following has highest EntropyA. MercuryB. HydrogenC. WaterD. Graphite |
| Answer» Correct Answer - B | |
| 2730. |
Which of the following statement(s) are incorrect ?A. Combustion of methane in an abiabatic rigid container will cause no charge in temperature of the system .B. It is possible to have both adiabatic reversible and adicbatic irreversible peocesses between two states.C. For a reaction involing only ideals gasese, occuring at constant temperature there will be no chager in internal energyD. P-V work is always non -zero when there is change in volume . |
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Answer» Correct Answer - a,b,c,d |
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| 2731. |
Entropy change for an adiabatic reversible process isA. zeroB. `+ve`C. `-ve`D. negative or zero |
| Answer» Correct Answer - A | |
| 2732. |
For process `H_(2)o(l)(100^(@)C,1atm)hArrH_(2)O(g)(100^(@)C,1 atm)` `{:(,"Column-I",,"Column-II"),((a),DeltaU,(p),0),((b),DeltaS ("system+surrounding"),(q),DeltaH),((c),"work",(r),"positive"),((d),"Heat involved",(s),"Negative"):}` |
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Answer» Correct Answer - `(a-r);(b-p);(c-s);(d-q)` |
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| 2733. |
A gaseous system is initially characterised by 500 mL volume and 1 atm pressure at 298 K. This system is allowed to do work as In isobaric conditions it expands to 800 mL resulting a decrease in pressure and temperature to 0.6 atm and 273 K respectively. (ii) In adiabatic conditions it is allowed to expand upto 800 mL and results a decrease in pressure and temperature to 0.6 atm and 273 K respectively. If Gibbs energy change in (i) is `DeltaG_(a)` and in (ii) is `DeltaG_(b)`, then what will be the ration of `(DeltaG_(a))/(DeltaG_(b))`? |
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Answer» Correct Answer - B `(DeltaG_(a))/(DeltaG_(b))=1`, as Gibbs energy is a state function and intial and final states are same in (i) and (ii). |
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| 2734. |
which of the following statements is incorrectA. The entropy of an isolated system increases in an irreversible processB. The entropy of an isolated system remains unchanged in a reversible processC. `Delta S_("system")` as well as `Delta S_("Surrounding")` are negative quantitiesD. Entropy of universe can never decrease |
| Answer» Correct Answer - C | |
| 2735. |
Entropy of the solutions is higher than that of pure liquid . Why? |
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Answer» Correct Answer - Dissolution fo solute makes the motion of solute particles free. Also the increased number of particles in mixed state increases disorderness Dissolution of solute makes the motion of solute particles free. Also the increased number of paritcles in mixed state increases disorderness. |
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| 2736. |
For reversible process at equilibrium, the change in entropy may be expressed asA. `DeltaS=Tq_(rev)`B. `Delta S=q_(rev)/T`C. `Deltas=(-DeltaH)/(T)`D. `Delta S=Delta H` |
| Answer» Correct Answer - B | |
| 2737. |
The change in enthalpy for an isobaric gaseous reaction (for an ideal gas system) is (are):A. `DeltaH=DeltaU+PDeltaV+VDeltaP`B. `DeltaH=DeltaU+PDeltaV`C. `DeltaH=DeltaU+DeltanRT`D. `DeltaH=DeltaU+PV` |
| Answer» Correct Answer - B::C | |
| 2738. |
Assertion. A process for which `DeltaS _("system") gt 0` as well as`DeltaH gt 0`, passes from non-spontaneous to spontaneous state as temperature is increased. Reason. At higher temperature `T DeltaS ` exceeds `DeltaH`.A. If both A and R are true,andR is the true explanation of A.B. If both A and R are true,but R is not the true explanation of A.C. If A is true, but R is falseD. If both A and R are false. |
| Answer» Correct Answer - a | |
| 2739. |
Which of the following statements is (are) correct?A. The entropy of the universe increaases and tends towards the maximum valueB. All natural process are irreversibleC. For the isothermal expansion of an ideal gas, `DeltaH` and `DeltaU` are equalD. All of these |
| Answer» Correct Answer - A::B::C::D | |
| 2740. |
The units of entropy areA. `J mol^(-1)`B. `J K^(-1) mol^(-1)`C. `J g^(-1)`D. `J K mol^(-1)` |
| Answer» Correct Answer - B | |
| 2741. |
What are the signs of `DeltaS` for the system and for the surrounding in each of the following processes? (a) Water boils in a teakettle on a hot stove. (b) Ice in an ice cube tray, left an a table melts. (c) A cup of coffee is reheated in a microwave oven. |
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Answer» Correct Answer - (a) `DeltaS_("sys")` is positive ; `DeltaS_("surr")` is negative; (b) `DeltaS_("sys")` is positive , `DeltaS_("surr")` is negative; (c) `DeltaS_("sys")` is positive, `DeltaS_("surr")` is negative. `(a) DeltaS_(sys)` is positive , `DeltaS_("surr")` is negative, (b)` DeltaS_(sys)` is positive , `DeltaS_("surr")` is negative, (c)` DeltaS_(sys)` is positive , `DeltaS_("surr")` is negative. |
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| 2742. |
For a spontaneous process, which of the following is true?A. `DeltaS_(sys)` positiveB. `Delta S_(surr)` positiveC. `Delta S_("total")` PositiveD. `Delta S_("total")` negative |
| Answer» Correct Answer - C | |
| 2743. |
Which has/have a positive value `(s)` of `DeltaH`?A. `H_(2)(g)to2H(g)`B. `H(g)toH^(+)(g)+e`C. `H_(2)(l)toH_(2)O(g)`D. `H^(+)(aq)+OH^(-)(ag)toH_(2)O` |
| Answer» Correct Answer - A::B::C | |
| 2744. |
An isolated system is that system in whichA. Can exchange matter with the surroundings.B. Can exchange energy with the surroundings.C. Can exchange both matter and energy with the surroundings.D. Cannot exchange either matter or energy with the surroundings. |
| Answer» In open system, heat and matter can be exchanged between system and surrounding. | |
| 2745. |
For which of the following processes is `DeltaS` negative?A. `H_(2)(g) rarr 2H(g)`B. `N_(2)(g,1atm) rarr N_(2)(g,5atm)`,C. `2SO_(3)(g) rarr 2SO_(2)(g) +O_(2)(g)`D. `C("diamond") rarr C("graphite")` |
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Answer» At higher pressure, `N_(2)(g)` will have less entropy `:. DeltaS` will be -ve. |
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| 2746. |
For a non-spontaneous reaction, at `30^(@)C, DeltaH gt 0` & `DeltaS gt 0`. The reaction becomes spontaneous, byA. Decreasing temperatureB. Increasing temperatureC. Maintaining temperature constantD. Does not maintain temperature |
| Answer» Correct Answer - B | |
| 2747. |
The internal energy `(U)` of an ideal gas decreases by the same amount as the work done by the system:A. The process must be adiabaticB. The process must be isothermalC. The process must be isobaricD. The temperature must decrease |
| Answer» Correct Answer - A::D | |
| 2748. |
If `q` is the amount of heat absorbed by the system and `W` the amount of work done on the system `(+ve)`, the change in the energy of the system is given by:A. `q=DeltaU+W`B. `q=DeltaU-W`C. `DeltaU=q-W`D. `DeltaU=W+q` |
| Answer» Correct Answer - B::D | |
| 2749. |
Which statements is correct?A. `((deltaH)/(deltaT))_(P)=((deltaU)/(deltaT))_(V)=R`B. `((deltaH)/(deltaT))_(P)gt((deltaU)/(deltaT))_(V)`C. `((deltaU)/(DeltaV))_(T)` for ideal gas is zeroD. All of these |
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Answer» Correct Answer - D `((deltaH)/(deltaT))_(P)=C_(P),((deltaU)/(deltaT))_(V)=C_(v)` Also `(deltaU//deltaV)T` for ideal gas=0 |
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| 2750. |
In a reaction, `DeltaH` and `DeltaS` both are more than zero. In which of the following cases, the reaction would not be spontaneous?A. `DeltaHgtTDeltaS`B. `TDeltaSgtDeltaH`C. `DeltaH=TDeltaS`D. `DeltaGlt0` |
| Answer» Correct Answer - A::C | |