InterviewSolution
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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.
| 1. |
A process is taking place at constant temperature and pressure. ThenA. `DeltaH`B. `DeltaH=TDeltaS`C. `DeltaH=0`D. `DeltaS=0` |
| Answer» Correct Answer - C | |
| 2. |
A reaction cannot take place spontaneously at any temperture whenA. both `DeltaH` and `DeltaS` are positiveB. both `DeltaH` and `DeltaS` are negativeC. `DeltaH` is negative and `DeltaS` is positiveD. `DeltaH` is zero and `DeltaS` is positive |
| Answer» Correct Answer - B | |
| 3. |
Assertion(A) : Absolute value of `H` cannot be determined. Reason(R ) : Absolute value of `E` cannot be determined.A. Both `A`and `R` are true and `R` is the correct explantion of `A`B. Both `A`and `R` are true and `R` is not a correct explantion of `A`C. `A` is true but `R` is falseD. `A` is false but `R` is true |
| Answer» Correct Answer - A | |
| 4. |
Assertion(A) : Decrease of free energy during the process under particular conditions provides a measure of its spontaneity. Reason(R ) : A spontaneous change must have +ve sign of `DeltaS_("total")`.A. Both `A`and `R` are true and `R` is the correct explantion of `A`B. Both `A`and `R` are true and `R` is not a correct explantion of `A`C. `A` is true but `R` is falseD. `A` is false but `R` is true |
| Answer» Correct Answer - B | |
| 5. |
Assertion:Absolute values of intenal energy of substances cannot be determined. Reason:It is impossible to determine exact values of constituent energies of the substances.A. Both `A`and `R` are true and `R` is the correct explantion of `A`B. Both `A`and `R` are true and `R` is not a correct explantion of `A`C. `A` is true but `R` is falseD. `A` is false but `R` is true |
| Answer» Correct Answer - A | |
| 6. |
Assertion(A) : Two systems which are both in thermal equilibrium with the third system are in thermal equilibrium with one another. Reason(R ) : The heat flows spontaneously from a system at high temperature to a system at low temperature.A. Both `A`and `R` are true and `R` is the correct explantion of `A`B. Both `A`and `R` are true and `R` is not a correct explantion of `A`C. `A` is true but `R` is falseD. `A` is false but `R` is true |
| Answer» Correct Answer - A | |
| 7. |
A sample consisting of `1mol` of a mono-atomic perfect gas `(C_(V) = (3)/(2)R)` is taken through the cycle as shown. Temperature at points `(1),(2)` and `(3)` respectively isA. `273K`, `546K`, `273K`B. `546K`, `273K`, `273K`C. `273K`, `273K`, `273K`D. `546K`, `546K`, `273K` |
| Answer» Correct Answer - A | |
| 8. |
Energy is associated with the orientation and distribution of molecules in space. Disordered crystals have higher entropy than ordered crystals and diffused gases have higher entropy than compressed gases. Entropy is also associated with molecular motion. As the temperature of a substance increases, random molecular motion increases hence entropy increases. Figure gives variation of entropy with temperature. At absolute zero `(-273^(@)C)` every substance is in solid state whose particles are rigidly fixed in a crystalline structure. If there is no residual orientational disorder, like that in `CO`, entropy of the substance is zero. Third law of thermodynamics states. At the absolute zero of temperature the entropy of every substance become zero and does become zero in case of perfectly crystalline structure. `understand(T to 0)(LtS)=0` In case of `CO` and `NO` molecules in solid state, there is randomness even at `0 K` due to their dipole moments hence entropy in such cases is not zero even at `0 K`. As the temperature is raised, the molecules begin to vibrate. The number of ways in which the vibrational energy can be distributed increases with increases in temperature and the entropy of solid increases steadily as the temperature increaes. At the melting point (mp) of the solid, there is a discontinous jump in entropy because there are many more ways of arranging the molecules in the liquid than in the solid. An even greater jump in entropy is observed at the boiling point (bp) because molecules in the gas are to free to occupy a more larger volume and randomness increases. From the figure representing enthalpy change of various transitions as indicated, a substance has maximum enthalpy present in A. Solid stateB. Liquid stateC. Gaseous stateD. Equal in all states. |
| Answer» Correct Answer - C | |
| 9. |
Energy is associated with the orientation and distribution of molecules in space. Disordered crystals have higher entropy than ordered crystals and diffused gases have higher entropy than compressed gases. Entropy is also associated with molecular motion. As the temperature of a substance increases, random molecular motion increases hence entropy increases. Figure gives variation of entropy with temperature. At absolute zero `(-273^(@)C)` every substance is in solid state whose particles are rigidly fixed in a crystalline structure. If there is no residual orientational disorder, like that in `CO`, entropy of the substance is zero. Third law of thermodynamics states. At the absolute zero of temperature the entropy of every substance become zero and does become zero in case of perfectly crystalline structure. `understand(T to 0)(LtS)=0` In case of `CO` and `NO` molecules in solid state, there is randomness even at `0 K` due to their dipole moments hence entropy in such cases is not zero even at `0 K`. As the temperature is raised, the molecules begin to vibrate. The number of ways in which the vibrational energy can be distributed increases with increases in temperature and the entropy of solid increases steadily as the temperature increaes. At the melting point (mp) of the solid, there is a discontinous jump in entropy because there are many more ways of arranging the molecules in the liquid than in the solid. An even greater jump in entropy is observed at the boiling point (bp) because molecules in the gas are to free to occupy a more larger volume and randomness increases. Which of the following process is spontaneous?A. Diffusion of perfume molecules from one side of the room to the otherB. Decomposition of solid `CaCO_(3)`C. Heat flow from a cold object to a hot objectD. Climbing up a mountain. |
| Answer» Correct Answer - A | |
| 10. |
Energy is associated with the orientation and distribution of molecules in space. Disordered crystals have higher entropy than ordered crystals and diffused gases have higher entropy than compressed gases. Entropy is also associated with molecular motion. As the temperature of a substance increases, random molecular motion increases hence entropy increases. Figure gives variation of entropy with temperature. At absolute zero `(-273^(@)C)` every substance is in solid state whose particles are rigidly fixed in a crystalline structure. If there is no residual orientational disorder, like that in `CO`, entropy of the substance is zero. Third law of thermodynamics states. At the absolute zero of temperature the entropy of every substance become zero and does become zero in case of perfectly crystalline structure. `understand(T to 0)(LtS)=0` In case of `CO` and `NO` molecules in solid state, there is randomness even at `0 K` due to their dipole moments hence entropy in such cases is not zero even at `0 K`. As the temperature is raised, the molecules begin to vibrate. The number of ways in which the vibrational energy can be distributed increases with increases in temperature and the entropy of solid increases steadily as the temperature increaes. At the melting point (mp) of the solid, there is a discontinous jump in entropy because there are many more ways of arranging the molecules in the liquid than in the solid. An even greater jump in entropy is observed at the boiling point (bp) because molecules in the gas are to free to occupy a more larger volume and randomness increases. Which has maximum entropy of vaporisation ?A. Ethanol `(l)`B. Benzene `(l)`C. Toluene `(l)`D. `CO_(2)(g)` |
| Answer» Correct Answer - A | |
| 11. |
Energy is associated with the orientation and distribution of molecules in space. Disordered crystals have higher entropy than ordered crystals and diffused gases have higher entropy than compressed gases. Entropy is also associated with molecular motion. As the temperature of a substance increases, random molecular motion increases hence entropy increases. Figure gives variation of entropy with temperature. At absolute zero `(-273^(@)C)` every substance is in solid state whose particles are rigidly fixed in a crystalline structure. If there is no residual orientational disorder, like that in `CO`, entropy of the substance is zero. Third law of thermodynamics states. At the absolute zero of temperature the entropy of every substance become zero and does become zero in case of perfectly crystalline structure. `understand(T to 0)(LtS)=0` In case of `CO` and `NO` molecules in solid state, there is randomness even at `0 K` due to their dipole moments hence entropy in such cases is not zero even at `0 K`. As the temperature is raised, the molecules begin to vibrate. The number of ways in which the vibrational energy can be distributed increases with increases in temperature and the entropy of solid increases steadily as the temperature increaes. At the melting point (mp) of the solid, there is a discontinous jump in entropy because there are many more ways of arranging the molecules in the liquid than in the solid. An even greater jump in entropy is observed at the boiling point (bp) because molecules in the gas are to free to occupy a more larger volume and randomness increases. For the following reaction `CaCO_(3)(s) to CaO(s)+CO_(2)(g)` If at `0 K`, `DeltaS` of this reaction is `X cal mol^(-1)` then entropy of `CO_(2)(g)` at `0 K` isA. `-X cal`B. `-2X cal`C. `+X cal`D. `0 cal` |
| Answer» Correct Answer - C | |
| 12. |
Assertion(A) : The mass and volume of a substance are the extensive properties and are proportional to each other. Reason(R ) : The ratio of mass of a sample to its volume is an intensive propertyA. Both `A`and `R` are true and `R` is the correct explantion of `A`B. Both `A`and `R` are true and `R` is not a correct explantion of `A`C. `A` is true but `R` is falseD. `A` is false but `R` is true |
| Answer» Correct Answer - B | |
| 13. |
A piece of ice kept at room temperature melts of its own. This reaction is governed by which law ?A. First law of thermodynamicsB. Zeroth law of thermodynamicsC. Second law of thermodynamicsD. Third law of thermodynamics |
| Answer» Correct Answer - C | |
| 14. |
For a chemical reaction, `DeltaG` will always be negative if,A. `DeltaH` and `TDeltaS` both are positiveB. `DeltaH` and `TDeltaS` both are negativeC. `DeltaH` is negative and `TDeltaS` is positiveD. `DeltaH` is positive and `TDeltaS` is negative |
| Answer» Correct Answer - C | |
| 15. |
Assertion(A) : Helium has lower entropy than `CO_(2)` gas which has lower entropy than gaseous benzene. Reason(R ) : The larger the complexity of molecule, the larger is its absolute entropy.A. Both `A`and `R` are true and `R` is the correct explantion of `A`B. Both `A`and `R` are true and `R` is not a correct explantion of `A`C. `A` is true but `R` is falseD. `A` is false but `R` is true |
| Answer» Correct Answer - A | |
| 16. |
In which reaction there will be increase in entropy ?A. `Na(s)+H_(2)O(l)toNaOH(aq)+1//2H_(2)(g)`B. `Ag^(+)(aq)+Cl^(-)(aq)toAgCl(s)`C. `H_(2)(g)+1//2O_(2)(g)toH_(2)O(l)`D. `Cu^(2+)+4NH_(3)(g)to[Cu(NH_(3))_(4)]^(2+)aq` |
| Answer» Correct Answer - A | |
| 17. |
Rate of a reaction can be expressed by Arrhenius equation as: `k = Ae^(-E_(a)//RT)` In this equation, `E_(a)` represents:A. The energy above which not all the colliding molecules will reactB. The energy below which colliding molecules will not reactC. The total energy of the reacting molecules at temperature `T`D. The fraction of molecules with energy greater than the activation enrgy of the reaction. |
| Answer» Correct Answer - B | |
| 18. |
Energy is associated with the orientation and distribution of molecules in space. Disordered crystals have higher entropy than ordered crystals and diffused gases have higher entropy than compressed gases. Entropy is also associated with molecular motion. As the temperature of a substance increases, random molecular motion increases hence entropy increases. Figure gives variation of entropy with temperature. At absolute zero `(-273^(@)C)` every substance is in solid state whose particles are rigidly fixed in a crystalline structure. If there is no residual orientational disorder, like that in `CO`, entropy of the substance is zero. Third law of thermodynamics states. At the absolute zero of temperature the entropy of every substance become zero and does become zero in case of perfectly crystalline structure. `understand(T to 0)(LtS)=0` In case of `CO` and `NO` molecules in solid state, there is randomness even at `0 K` due to their dipole moments hence entropy in such cases is not zero even at `0 K`. As the temperature is raised, the molecules begin to vibrate. The number of ways in which the vibrational energy can be distributed increases with increases in temperature and the entropy of solid increases steadily as the temperature increaes. At the melting point (mp) of the solid, there is a discontinous jump in entropy because there are many more ways of arranging the molecules in the liquid than in the solid. An even greater jump in entropy is observed at the boiling point (bp) because molecules in the gas are to free to occupy a more larger volume and randomness increases. Predict the sign of `Delta S` in the system for each of the following process `(I) CO_(2)(s)toCO_(2)(g)` `(II) CaSO_(4)(s)toCaO(s)+SO_(3)(g)` `(III) N_(2)(g)+3H_(2)(g)to2NH_(3)(g)` `(IV) I_(2)(s) to I_(2)(aq)`A. `{:(I,II,III,IV),(+ve,+ve,-ve,+ve):}`B. `{:(I,II,III,IV),(+ve,-ve,-ve,+ve):}`C. `{:(I,II,III,IV),(-ve,-ve,+ve,+ve):}`D. `{:(I,II,III,IV),(+ve,-ve,-ve,-ve):}` |
| Answer» Correct Answer - A | |
| 19. |
Energy is associated with the orientation and distribution of molecules in space. Disordered crystals have higher entropy than ordered crystals and diffused gases have higher entropy than compressed gases. Entropy is also associated with molecular motion. As the temperature of a substance increases, random molecular motion increases hence entropy increases. Figure gives variation of entropy with temperature. At absolute zero `(-273^(@)C)` every substance is in solid state whose particles are rigidly fixed in a crystalline structure. If there is no residual orientational disorder, like that in `CO`, entropy of the substance is zero. Third law of thermodynamics states. At the absolute zero of temperature the entropy of every substance become zero and does become zero in case of perfectly crystalline structure. `understand(T to 0)(LtS)=0` In case of `CO` and `NO` molecules in solid state, there is randomness even at `0 K` due to their dipole moments hence entropy in such cases is not zero even at `0 K`. As the temperature is raised, the molecules begin to vibrate. The number of ways in which the vibrational energy can be distributed increases with increases in temperature and the entropy of solid increases steadily as the temperature increaes. At the melting point (mp) of the solid, there is a discontinous jump in entropy because there are many more ways of arranging the molecules in the liquid than in the solid. An even greater jump in entropy is observed at the boiling point (bp) because molecules in the gas are to free to occupy a more larger volume and randomness increases. Out of the following statements : `I`, `II` and `III`. `I` . A system may be a complex as a human body as simple as a mixture consiting of a drop of water. `II`. A large system is said to be microscopic when it consists of a large number of molecules, atoms or ions. `III`. Pressure, volume, temperature and surface area are some macroscopic properties. Select correct statementsA. `I`, `II`, `III`B. `I`, `II`C. `I`, `IV`D. `II`, `III` |
| Answer» Correct Answer - A | |
| 20. |
Energy is associated with the orientation and distribution of molecules in space. Disordered crystals have higher entropy than ordered crystals and diffused gases have higher entropy than compressed gases. Entropy is also associated with molecular motion. As the temperature of a substance increases, random molecular motion increases hence entropy increases. Figure gives variation of entropy with temperature. At absolute zero `(-273^(@)C)` every substance is in solid state whose particles are rigidly fixed in a crystalline structure. If there is no residual orientational disorder, like that in `CO`, entropy of the substance is zero. Third law of thermodynamics states. At the absolute zero of temperature the entropy of every substance become zero and does become zero in case of perfectly crystalline structure. `understand(T to 0)(LtS)=0` In case of `CO` and `NO` molecules in solid state, there is randomness even at `0 K` due to their dipole moments hence entropy in such cases is not zero even at `0 K`. As the temperature is raised, the molecules begin to vibrate. The number of ways in which the vibrational energy can be distributed increases with increases in temperature and the entropy of solid increases steadily as the temperature increaes. At the melting point (mp) of the solid, there is a discontinous jump in entropy because there are many more ways of arranging the molecules in the liquid than in the solid. An even greater jump in entropy is observed at the boiling point (bp) because molecules in the gas are to free to occupy a more larger volume and randomness increases. Which has the highest entropy per mol of the substance ?A. `H_(2)` at `25^(@)C` at `1` atmB. `H_(2)` at STPC. ` H_(2)` at `100 K` at `1` atmD. H_(2)` at `0 K` at `1` atm |
| Answer» Correct Answer - A | |
| 21. |
The enthalpy change in the reaction : `2CO+O_(2)to2CO_(2)` is termed asA. enthalpy of reactionB. enthalpy of fusionC. Enthalpy of combustionD. enthalpy of formation |
| Answer» Correct Answer - C | |
| 22. |
For an adiabatic process :A. `T=` constantB. `q=0`C. `q=` constantD. `W=0` |
| Answer» Correct Answer - C | |
| 23. |
Which is correct for an endothermic reaction ?A. `DeltaE` is negativeB. `DeltaH` is negativeC. `DeltaH` is positiveD. `DeltaH` is equal to zero |
| Answer» Correct Answer - C | |
| 24. |
Assertion(A) : For the combustion reactions, the value of `DeltaH` is always negative. Reason(R ) : The combustion reactions are always endothermic.A. Both `A`and `R` are true and `R` is the correct explantion of `A`B. Both `A`and `R` are true and `R` is not a correct explantion of `A`C. `A` is true but `R` is falseD. `A` is false but `R` is true |
| Answer» Correct Answer - C | |