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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.
| 101. |
`2 mol` of chlorine gas occupies a volume of `800 mL` at `300 K` and `5xx10^(6) Pa` pressure. Calculate the compressibility factor of the gas. `(R=0.083 L "bar" K^(-1)mol^(-1))`. Comment, whether the gas is more compressible or less compressible under these conditions. |
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Answer» Calculation of ideal volume `(V_(ideal))` `V_(ideal)=(nRT)/(P)=((2.0 mol)(0.083 "bar" K^(-1) mol^(-1))(300 K))/((5xx10^(6)//10^(5))"bar")` `=1.004 L` Now, `Z=(V_(real))/(V_(ideal))=(800 mL)/(1.004xx10^(3)mL)=0.796` As `Z` is less than `1`, it means that the gas is more compressible under these conditions. |
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| 102. |
When a student was given a viscometer, the liquid was sucked with difficulty, the liquid may be:A. benzeneB. tolueneC. waterD. glycerine |
| Answer» Correct Answer - D | |
| 103. |
At constant volume for a fixed number of mole of a gas the pressure of a gas increase with rise of temperature due to .A. increase in average molecular speedB. increased rate of collisions amongst moleculesC. increase in molecular attractionD. decrease in mean free path. |
| Answer» Correct Answer - A | |
| 104. |
The density of steam at `100^(@)C` and `10^(5) Pa` pressure is `0.6 Kgm^(-3)`. Calculate the compresibility factor of steam. |
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Answer» We know `Z=(PV)/(nRT)` and `d=(PM)/(RT)` `thereforeZ=(PV)/(nRT)=(PV)/((m//w)RT)=(MPV)/(wRT)` Since `d=(w)/(V)` `thereforeZ=(MP)/(dRT)=((18xx10^(-3))xx10^(5))/(0.6xx8.31xx373.15)=0.967` |
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| 105. |
Mark the correct statement.A. Surface tension of a liquid increases with temperatureB. Addition of chemicals reduces the surface tension of liquidC. Stalagmometer is used for measuring viscosity of liquidD. Viscosity of the liquid does not depend intermolecular forces |
| Answer» Correct Answer - B | |
| 106. |
Which of following correctly represents the relation between capillary rise `h` and capillary radius `r`?A. B. C. D. |
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Answer» Correct Answer - B Capillary rise decreases with increase in the radius of tube |
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| 107. |
Which of following correctly represents the relation between capillary rise `h` and capillary radius `r`?A. B. C. D. |
| Answer» Capillary rise decreases with increase in the radius of tube. | |
| 108. |
As the concentration of molecules in the vapor phase increases, some molecules return to the liquid phase , a process calledA. solidficationB. crystallizationC. diffusionD. condensation |
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Answer» Correct Answer - D Condensation occurs because a molecule striking the liquid surface becomes trapped by intermolecular forces in the liquid. |
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| 109. |
With the increasing molecular mass of a liquid the velocity:A. decreasesB. increasesC. no effectD. all wrong |
| Answer» Correct Answer - B | |
| 110. |
Which of the given sets of temperature and pressure will cause a gas to exhibit the greatest deviation from ideal gas behaviour?A. `100^(@)C` and `4 atm`B. `100^(@)C` and `2 atm`C. `-100^(@)C` and `4 atm`D. `0^(@)C` and `2 atm` |
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Answer» Correct Answer - C Gas deviates from ideal gas behaviour to real gas (according to van der Waals at low temperature and high pressure) |
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| 111. |
Which of the following is most suitable for liquefaction?A. `T gt T_(C ) & P gt PC`B. `T lt T_(C )&Plt P_(C )`C. `T lt T_(C )& P gt P_(C )`D. `T lt T_(C )& P=0` |
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Answer» Correct Answer - C For liquefaction `T lt T_(C )& P gt P_(C )` |
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| 112. |
The boiling point of a liquid is the temperature at which the vapor pressure of the liquid is equal toA. 760 torrB. external forceC. 750 torrD. 700 torr |
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Answer» Correct Answer - B The normal boiling point is the temperature at which the vapor pressure of a liquid is equal to exactly one atmosphere (760 torr), while the standard boiling poin is the temperature at which the vapor pressure of a liquid is equal to exactly one bar (750 torr). |
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| 113. |
Vapor pressure of a liquid changes with …… of the liquid.A. volumeB. surface areaC. temperatureD. all of these |
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Answer» Correct Answer - C Equlibrium vapor pressure is the maximum vapor pressure a liquid exerts at a given temperature and it is a constant at constant temperature . Because the rate of evaporation increases with increasing temperaure , vapor pressures of liquids always increase as temperature increases. As long as some liquid remains in contact with the vapor , the equilibrium vapor pressure does not depend on the amount (volume of surface area ) of the liquid. The number of molecules with higher kinetic energies is greater at higher temperature , and therefore , so is the evaporation rate. Notice that the increase in vapor pressure is not linear with temperature. |
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| 114. |
Which state of matter has a definate volume but no definite shape ? |
| Answer» Correct Answer - Liquid. | |
| 115. |
The rise of a liquid in a capillary tube is due to :A. viscosityB. osmosisC. diffusionD. surface tension |
| Answer» Correct Answer - B | |
| 116. |
Surface tension decreases with increase in ....... |
| Answer» Correct Answer - Temperature | |
| 117. |
Vapor pressure of a liquid decreases with increases in ........ |
| Answer» Correct Answer - Pressure | |
| 118. |
With regard to the gaseous state of matter which of the following statements are correct ?A. Complete order of moleculesB. Complete disorder of moleculesC. Random motion of moleculesD. Fixed position of molecules |
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Answer» Correct Answer - B::C In a gaseous state, there is a complete disorder of molecules as there is random motion of molecules. |
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| 119. |
With increase in temperature, the fluidity of liquidsA. increasesB. decreasesC. remains constantD. may increase of decrease |
| Answer» Correct Answer - A | |
| 120. |
Vapour pressure of a liquid decreases with increase in ........A. decrease in temperatureB. increase in temperatureC. increase in surface areaD. increase in volume . |
| Answer» Correct Answer - B | |
| 121. |
The root mean square velocity of an ideal gas in a closed container of fixed volume is increased from `5xx10^(4)cms^(-1)` to `10xx10^(4)cm s^(-1)`. Which of the following statements correctly explains how the change is accomplished?A. By heating the gas, the temperature is doubled.B. By heating the gas, the pressure is quadrupled.C. By heating the gas, the temperature is quadrupled.D. By heating the gas, the pressure is doubled. |
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Answer» Hint: `mu_(rms)=sqrt((3RT)/(M))` or `sqrt((3PV)/(M))` `(mu_(rms))_(1)=5xx10^(4)cm s^(-1)` `(mu_(rms))_(2)=10xx10^(4) cm s^(-1)` `P_(1)=((mu_(rms))_(1)^(2)xxM)/(3V)=(5xx10^(4))^(2)xx(M)/(3V)` `P_(2)=((mu_(rms))_(2)^(2)xxM)/(3V)=(10xx10^(4))^(2)xx(M)/(3V)` or `(P_(2))/(P_(1))=((10xx10^(4))^(2))/((5xx10^(4))^(2))=(100)/(25)=4` `:. P_(2)=4xxP_(1)` Similarily, `T_(2)=4xxT_(1)` |
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| 122. |
Dispersion forces are weak attractive forces are important only over extremely short distances because they vary asA. `1//d^(6)`B. `1//d^(4)`C. `1//d^(7)`D. `1//d^(5)` |
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Answer» Correct Answer - C Interaction energy `("force" xx "distance")` is inversely proportional to `1//d^(6)`. These forces are present between all types of molecules or atoms in condensed phases but are weak for small molecules. |
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| 123. |
A graph between vapour pressure and temperature of few liquids is given below . Study the graph and answer the following : Which of the following statements is true ?A. Boiling point of a liquid is the temperature at which its vapour pressure become equal to atmospheric pressure .B. Boiling point of water can be increased by increasing the pressure above the atmospheric pressure .C. Liquid C has higher boiling point than B due to higher intermolecular forces .D. All of the these . |
| Answer» Correct Answer - D | |
| 124. |
How does the surface tension of a liquid vary with increase in temperature ?A. Remains sameB. DecreasesC. IncreasesD. No regular pattern is followed |
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Answer» Correct Answer - B Surface tension decreases with increase of temperature. |
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| 125. |
Using van der Waals equation, calculate the constant `a` when `2 mol` of a gas confined in a `4 L` flasks exerts a pressure of `11.0 atm` at a temperature of `300 K`. The value of `b` is `0.05 L mol^(-1)`. |
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Answer» The van der Waals equation of state for a gas is `(P+(an^(2))/(V^(2)))(V-nb)=nRT` `:. (11+(axx2^(2))/(4^(2)))(4-2xx0.05)=2xx0.0821xx300` or `a=6.46 atm L^(2) mol^(-2)` |
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| 126. |
Surface tension does not vary withA. temperatureB. concentrationC. size of the surfaceD. vapour pressure . |
| Answer» Correct Answer - C | |
| 127. |
In the given figur I is surface molecule whereas II is interior moleculr . Choose the correct option .A. I results net attraction into the liquid .B. II are attracted in all directions .C. Both (a) and (b) .D. Neither (a) nor (b) . |
| Answer» Correct Answer - C | |
| 128. |
Certain volume of a gas exerts on its walls some pressure at a particular temperature . It has been found that by reducing the volume of the gas to half of its original value the pressure become twice that of the initial value at constant temperature . this happens becauseA. mass of the gas increases with pressureB. speed of the gas molecules decreasesC. more number of gas molecules strike the surface per secondD. gas molecules attract each other . |
| Answer» Correct Answer - C | |
| 129. |
Which of the following is not a correct expression regarding the units of coefficient of viscosity ?A. dyne `cm^(-2) s`B. dyne `cm^(2) s^(-1)`C. N `m^(-2) s`D. Pa s |
| Answer» Correct Answer - B | |
| 130. |
Which of the following expressions regarding the unit of coefficient of viscosity is not true?A. dyne `cm^(-2) sec`B. dyne `cm^(2)sec^(-1)`C. `Nm^(-2)sec`D. 1 poise `= 10^(-1)Nm^(-2)sec` |
| Answer» Correct Answer - C | |
| 131. |
Viscosity of a liquid is increased by:A. increases in temperatureB. decreases in molecular sizeC. increase in molecular sizeD. none of the above |
| Answer» Correct Answer - C | |
| 132. |
Which of the following is correct regarding viscosity?A. It is internal resistance of a liquid to flowB. It increases with increase in temperature of the liquidC. Coefficient of viscosity is not represented by `eta`D. All of the above |
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Answer» Correct Answer - A Viscosity is the internal resistance of a liquid to flow |
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| 133. |
Increase in kinetic energy can overcome intermolecular forces of attraction. How will the viscosity of liquid be affected by the increase in temperature ?A. IncreaseB. No effectC. DecreaseD. No regular pattern will be followed |
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Answer» Correct Answer - C Viscosity of liquid decreases with increase in temperature. |
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| 134. |
An open flask contains air at `27^(@)C` Calculate the temperature at which it should be heated so that (a) `(1)/(3)` rd of air measured at `27^(@)C` escapes out |
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Answer» Correct Answer - `177^(@)C` Let the initial number of moles of `27^(@)C (300 K)` be `n` No. of moles of air left when heated to `TK = n - n/3 = (2n)/(3)` At constant pressure `n_(1)T_(1) = n_(2)T_(2)` or `n xx 300 = (2n)/(3) xx T` or `T = (300 xx 3)/(2) = 450 K = 177^(@)C` |
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| 135. |
The temperature above which the gas cannot be liquefied by any amount of pressure is called…………………... |
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Answer» Correct Answer - critical temperature |
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| 136. |
Assertion: The heat absorbed during the isothermal expansion of an ideal gas against vacuum is zero. Reason: The volume occupied by the molecules of an ideal gas is zero.A. If both (`A`) and (`R`) are correct and (`R`) is the correct explanation of (`A`).B. If both (`A`) and (`R`) are correct, but (`R`) is not the correct explanation of (`A`).C. If (`A`) is correct, but (`R`) is incorrect.D. If (`A`) is incorrect, but (`R`) is correct. |
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Answer» Correct Answer - A::B::C::D `(delU//delV)_(T)=0` (for ideal gas), because heat depends upon temperature. |
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| 137. |
`NH_(3)` can be liquefied at ordinary temperature without the application of pressure. But `O_(2)` cannot be because :A. its critical temperature is very highB. its critical temperature is very lowC. its critical temperature is modrateD. its critical temperature is higher than that of ammonia. |
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Answer» Correct Answer - B Critical temperature of `O_(2)` is very low `(154.3 K)` while of `NH_(3)` is above the room temperature. |
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| 138. |
An ideal gas can never be liquefied because .A. its critical temperature is always above `0^(@)C`B. its molecules are relatively smaller in sizeC. it solidifies before becoming a liquidD. forces operating between its molecules are negligible |
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Answer» Correct Answer - D Gases can be liquefied by lowering the temperature and increasing the pressure. An ideal gas have no intermolecular force of attraction, so it cannot be liquefied by applying high pressure and decreasing temperature. |
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| 139. |
Assertion: The pressure of a fixed amount of an ideal gas is proportional to its temperature. Reason: The Frequency of collisions and their impact both increase in proportion of the square root of temperature.A. If both (`A`) and (`R`) are correct and (`R`) is the correct explanation of (`A`).B. If both (`A`) and (`R`) are correct, but (`R`) is not the correct explanation of (`A`).C. If (`A`) is correct, but (`R`) is incorrect.D. If (`A`) is incorrect, but (`R`) is correct. |
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Answer» Assertion is true, reason is true, reason is not the correct explanation for assertion. The pressure of a fixed amount of an ideal gas is proportional to its temperature. `v_(rms) prop sqrt(T)` Collision frequency is directly proportional to `v_(rms)`. On increasing the collision frequency, the pressure increases. |
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| 140. |
Assertion: The pressure of a fixed amount of an ideal gas is proportional to its temperature. Reason: Frequency of collisions and their impact both increase in proportion of the square root of temperature.A. If both (`A`) and (`R`) are correct and (`R`) is the correct explanation of (`A`).B. If both (`A`) and (`R`) are correct, but (`R`) is not the correct explanation of (`A`).C. If (`A`) is correct, but (`R`) is incorrect.D. If (`A`) is incorrect, but (`R`) is correct. |
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Answer» Correct Answer - A::B::C::D `P prop T` |
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| 141. |
Which of the following volume-temperature `(V-I)` plots represents the behaviour of `1 "mole"` of an ideal gas at the atmospheric pressure?A. B. C. D. |
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Answer» Correct Answer - C Volume of 1 mole of ideal gas at `273 K` and `1 atm`. Pressure `22.4 L` Volume of 1 mole of ideal gas at 373 K and 1 atm. Pressure `= (RT)/(P)` ` = (0.0831 xx 373)/(1) = 30.58 L` |
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| 142. |
Which of the following volume-temperature `(V-I)` plots represents the behaviour of `1 "mole"` of an ideal gas at the atmospheric pressure?A. B. C. D. |
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Answer» Correct Answer - C |
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| 143. |
Which of the following plots are correct ?A. B. C. D. |
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Answer» Correct Answer - B,C,D V vs. P at constant T is a hyperbola. Hence, (a) is wrong. All others are correct. |
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| 144. |
Which of the following volume (V)-temperature (T) plots represents the behaviour of one mole of an ideal gas at one atmospheric pressure ?A. B. C. D. |
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Answer» Correct Answer - C Volume of 1 mole of an ideal gas at 273 K and atm is 22.4 L. Volume at 373 K and 1 atm pressure `V=(RT)/(P)=(0.082xx373)/(1)=30.58" L"~~30.6" L"` |
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| 145. |
Calculate the molar mass of an unknown gas which diffuses 1.117 times faster than oxygen oxygen gas through same aperture under the same conditions of temperature and pressure. |
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Answer» Correct Answer - A::B `(r_(X))/(r_(O_(2)))=sqrt((M_(O_(2)))/(M_(X)))" or "1.117=sqrt((32)/(M_(X)))" or "M_(X)=(32)/((1.117)^(2))=25.65 g mol^(-1)` |
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| 146. |
Silver crystallises in a face-centred cubic unit cell. The density of Ag is `10.5 g cm^(-3)` . Calculate the edge length of the unit cell. |
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Answer» For face-centred cubic unit, Z=4 We know that , `V=(ZxxM)/(N_(0)xxd)` `=(4xx108)/((6.023xx10^(23))xx10.5)=6.83xx10^(-23)` `=68.3xx10^(-24)` Let a be the edge length of the unit cell. So, `V=a^(3)` or `a^(3)=68.3xx10^(-24)` `a=(68.3xx10^(-24))^(1//3) cm` `=4.09xx10^(-8)` cm =409 pm |
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| 147. |
Which of the following is not a molecular solid ?A. Dry iceB. NaphthaleneC. GlucoseD. Silicon |
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Answer» Correct Answer - D Silicon is a network solid. |
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| 148. |
An element crystallizes into a structure which may be describes by a cubic type of unit cell having one atom on each corner of the cube and two atoms on one of its diagonals. If the volume of this unit cell is `24xx10^(-24)cm^(3)` and density of element is `7.2g cm^(-3)` . Calculate the number of atoms present in `200g` of element. |
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Answer» Number of atoms in a unit cell (Z)=1+2=3 `Z=(l^(3)xxrhoxxN)/(M)` `M=(l^(3)xxrhoxxN)/(Z)` `=(24xx10^(-24)xx7.2xx6.023xx10^(23))/(3)=34.69` Number of atoms `=("Mass")/("Molar mass")xx6.023xx10^(24)` `(200)/(34.69)xx6.023xx10^(23)=3.47xx10^(24)` |
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| 149. |
Calcium crystallises in a face `-` centred cubic unit cell with `a=556nm`. Calculate the density if it contained `0.1%` Vaccancy defects. |
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Answer» (i) Frenkel defect does not alter the density of solid. `d=(MZ)/(a^(3)N)=(40xx4)/((0.556xx10^(-7))^(3)xx6.023xx10^(23)` `=1.5455g//cm^(3)` (ii) Shottky defect lowers the density of solid `Z=4=(4xx0.1)/(100)=3.996` `d=(40xx3.996)/((0.556xx10^(-7))^(3)xx6.023xx10^(23)` `=1.5455g//cm^(3)` |
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| 150. |
If helium is allowed to expand in vacuum, it liberates heat becauseA. Helium is an inert gasB. Helium is an ideal gasC. The critical temperature of helium is very lowD. Helium is one of the lightest gases |
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Answer» Correct Answer - A::C |
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