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Path to success KOTA (RAJASTHAN )
Single correct :
1. The temperature (K) at which a pure sample of an ideal gas not only exhibit a pressure of one atm but also
has a concentration 1 mole/dm3. [3]
(A) 12 K (B) 312 K (C) 285 K (D) 273 K
Ans. (A)
2. At the top of the mountain the thermometer reads 0°C and the barometer reads 710 mm Hg. At the bottom of
the mountain the temperature is 30°C and presure is 760 mm Hg. Ratio of density of air at the top with that at
the bottom is [3]
(A) 1 : 1 (B) 1.04 : 1 (C) 1 : 1.04 (D) 1 : 1.5
Ans. (B)
3. A liquid of density 1.70 gm/ml is filled in the barometer, in place of mercury. What should be the length of
liquid column, if another barometer filled with mercury, is measuring 75 cm pressure? Density of mercury is
13.6 gm/ml.
(A) 75 cm (B*) 600 cm (C) 9.375 cm (D) 6 000 cm
4. At a constant temperature a gas occupies a volume of 200 ml at a pressure of 0.720 bar. It is subjected to an
external pressure of 0.900 bar. What is the resulting volume of the gas?
(A*) 160 ml (B) 320 ml (C) 80 ml (D) 400 ml
5. 2.5 L of a sample of a gas at 27 C and 1 bar pressure is compressed to a volume of 500 ml keeping the
temperature constant, the percentage increase in pressure is
(A) 100% (B*) 400% (C) 500% (D) 80%
6. A volume of 10 ml of gaseous C4Hx exactly requires 55 ml of O2 for complete combustion. The value of x is-
(A) 4 (B*) 6 (C) 8 (D) 10
7. At 1 atm pressure and 0°C a sample of gas has a volume 0.2 lit. At 273°C and 1 atm pressure, its volume
will be:
(A) 0.8 lit (B) 0.4 lit (C) 1.4 lit *(D) 1.8 lit
8. A gas occupies 100 mL at 720 mm pressure. At what pressure it occupies a volume of 84 mL?
*(A) 857.14 mm (B) 875.41 mm (C) 825.4 mm (D) 895.15 mm
Subjective type
9. 3.7 gm of a gas at 25º C occupy the same volume as 0.184 g H2 at 17ºC at same pressure. What is molecular
weight of gas?
Ans. 41.326
10. The pressure exerted by 12 gm of an ideal gas at temperature tºC in a vessel of volume V litre is one atm.
When the temperature is increased by 10 degree at the same volume, the pressure increases by 10%. Calculate
the temperature t and volume V. (Molecular weight of the gas = 120)
Ans. 100 K, 0.82 litre
PHYSICAL CHEMISTRY /R # 01 E-1 /2
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Path to success KOTA (RAJASTHAN )
Path to success KOTA (RAJASTHAN )
Single correct :
1. At 27°C and 0.821 atm pressure the volume of 2.8 g of carbon mono-oxide is: [R = 0.0821 lit atm/mol K] :
(A) 30 lit *(B) 3 lit (C) 1.5 lit (D) 0.3 lit
2. By the ideal gas law the pressure of 0.60 mol NH3 gas in a 3.00 litre vessel at 25°C is:
(A) 48.9 atm *(B) 4.89 atm (C) 0.489 atm (D) 489 atm
3. If volume of 2 mol of an ideal gas at 540 K is 44.8 litre, its pressure is:
*(A) 2 atm (B) 4 atm (C) 5 atm (D) 6 atm
4. Collapsible balloon is inflated to a volume of 10 L at a pressure of 1 atm. When the balloon is immersed
to the bottom of a lake, its volume reduces to 1.25 L. Assuming 1 atm pressure to be equivalent to 10
m column of water and no change in temperature, the depth of the lake will be :
*(A) 70 m (B) 80 m (C) 90 m (D) None of these
5. 190.0 ml of N2 was collected in a jar over water at some temperature, water level inside and outside the
jar standing at the same height. If barometer reads 740 mm Hg and aqueous tension at the temperature
of the experiment is 20 mm Hg, the volume of the gas at 1 atm pressure and at the same temperature
would be :
(A) 185.0 mL *(B) 180.0 mL (C) 195.0 mL (D) 200 mL
6. 14 gm of N2 and 36 gm of ozone are at the same pressure and temperature. Their volumes will be related
as :
(A) 2 VN 2 3VO 3 *(B) 3VN 2 2 VO 3 (C) 3VN 2 4 VO 3 (D) 4 VN 2 3VO 3
7. Equal masses of hydrogen gas and oxygen gas are placed in a closed container at a pressure of 3.4 atm.
The contribution of hydrogen gas to the total pressure is :
(A) 1.7 atm (B) 0.2 atm *(C) 3.2 atm (D) 3.02 atm
8. A gas at a pressure of 5.0 atm is heated from 0° to 546°C and simultaneously compressed to
one-third of its original volume. Hence final pressure is
(A) 10.0 atm (B) 30.0 atm *(C) 45.0 atm (D) 5.0 atm
9. A closed container contains N molecules at P atm and TK. If the absolute temperature is doubled,
(A) number of molecules present in the container will become 2N
(B) number of molecules present in the container will become N/2
(C*) gas pressure become 2 P
(D) gas pressure become P/2
10. The temperature of an ideal gas can be raised by
(A) decreasing the volume but keeping the quantity and pressure fixed
(B*) decreasing the quantity but keeping the pressure and volume fixed
(C) decreasing the pressure but keeping the quantity and volume fixed
(D) decreasing the pressure and volume but keeping the quantity fixed
PHYSICAL CHEMISTRY /R # 02 E-1 /1
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Path to success KOTA (RAJASTHAN )
Path to success KOTA (RAJASTHAN )
Single correct :
1. The molar volume of CO2 is maximum at
(A) 273K and 1 atm (B*) 546K and 1 atm (C) 273K and 2 atm (D) 546K and 2 atm
2. A container of volume 2 litre contains H2 gas at 300K as shown (Patm= 76 cm of Hg)
4cm 3
Liquid A (density = 27.2 gm/cm )
H2 2cm
Gas Liquid B (density = 6.8 gm/cm3)
3
Hg(l) (density = 13.6g m/cm )
The pressure (in cm Hg) of H2 in the container is -
(A) 82 cm *(B) 85 cm (C) 80 cm (D) 81 cm
3. A vessel contains 1 mole of O2 gas at a temperature T. The pressure of the gas is P. An identical vessel containing
1 mole of He gas at a temperature 2T has a pressure of
(A) P / 8 (B) P (C*) 2P (D) 8 P
4. If the difference in the level of Hg in an open arm manometer [One end open to atmosphere and other end is
connected to gas chamber] is 5 mm . Then what can be the pressure of gas ?
(Given : 1 atm = 1.01325 × 105 N/m2)
(A) 765 mm of Hg (B) 755 mm of Hg (C) 760 torr (D) 700 torr
Ans. (A,B)
5. In two different vessels X and Y, H2O () is kept at the same temperature, the vacant space left over the
W H2 O x
surface of H2O() is V and 3V respectively. What is the mass ratio
W H2 O y
of vapours in two vessels?
*(A) 1 : 3 (B) 3 : 1 (C) 1 : 4 (D) 1 : 1
6. At constant pressure, what should be the percentage decrease in the density of an ideal gas for a 10% increase
in the absolute temperature?
(A) 10% (B*) 9.1% (C) 11% (D) 12.09%
7. A quantity of hydrogen gas occupies a volume of 30.0 mL at a certain temperature and pressure. What volume
would half this mass of hydrogen occupy at triple the absolute temperature if the pressure were one-ninth that
of the original gas?
(A) 270 mL (B) 90 mL *(C) 405 mL (D) 135 mL
8. Identify the correct statements when a fixed amount of ideal gas is heated in a container fitted with a movable
piston always operating at constant pressure.
(A) Average distance travelled between successive collisions will decreases.
(B) Collisions frequency increases since speed of the molecules increases with increase in temperature.
(C) Average relative speed of approach remains unaffected.
*(D) Average angle of approach remains unaffected.
PHYSICAL CHEMISTRY /R # 02 E-1 /2
TM
Path to success KOTA (RAJASTHAN )
9. The postulates of the kinetic molecular theory of gases include all those that follow except :
(A) no forces exist between molecules.
(B) molecules are point masses.
(C) molecules are in random motion.
*(D) molecules are repelled by the walls of the container.
10. Equal volumes of two gases at same temperature and pressure have :
(A) equal masses (B) Avogadro's number of molecules
(C) identical chemical composition *(D) the same number of molecules
E-2 /2 PHYSICAL CHEMISTRY /R # 02
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Path to success KOTA (RAJASTHAN )
Path to success KOTA (RAJASTHAN )
Single correct :
1. Two flasks A and B of equal volumes maintained at temperatures 300 K and 600 K contain equal mass
of H2 and CH4 respectively. The ratio of total translational kinetic energy of gas in flask A to that in flask
B is :
(A) unity (B) 2 *(C) 4 (D) 0.25
2. 2 gm H2 diffuses in 10 min, then how long will 8gm O2 diffuse under same conditions -
(A) 5 min *(B) 10 min (C) 2 min (D) 20 min
3. A vessel contains equal masses of three gases A,B,C and recorded a pressure of 3.5 bar at 25°C. The
molecular mass of C is twice that of B and molecular mass of A is half of B. Find the partial pressure of B
(in bar) in the vessel
(A) 3 (B) 2 (C) 4 *(D) 1
4. If X is the total number of collisions which a gas molecule registers with other molecules per unit time under
particular conditions, then the collision frequency of the gas containing N molecules per unit volume is -
(A) X/N (B) NX (C) 2NX (D) NX/2
5. Which of the following gas molecule has the longest mean free path at the same pressure and temperature
(A) H2 (B) N2 (C) O2 (D) Cl2
6. Pressure versus temperature graph of an ideal gas of equal number of moles of different volumes is plotted as
shown in figure. Choose the correct alternatives -
P
4
2
3
1
T
*(A) V1 = V2 , V3 = V4 and V2 > V3 (B) V1 = V2 , V3 = V4 and V2 < V3
(C) V1 = V2 = V3 = V4 (D) V4 > V3 > V2 > V1
7. 50 mL of hydrogen diffuses out through a small hole of a vessel, in 20 minutes. The time taken by 40 mL of
oxygen to diffuse out is :
(A) 8 minute (B) 12 minute (C) 32 minute *(D) 64 minute
8. The temperature of gas is raised from 27°C. The root mean square speed of the gas :
(A) gets halved *(B) gets doubled (C) remains same (D) gets 927/27 times
9. An ideal gas, obeying kinetic theory of gases cannot be liquefied, because :
(A) its critical temperature is above 0°C (B) its molecules are relatively small in size
(C) it solidifies before becoming a liquid *(D) forces acting between its molecules are negligible
10. Which of the following expressions correctly represents the relationship between the average molar kinetic
energy, K.E. of CO and N2 molecules at the same temperature?
(A) KECO < KE N 2
(B) KECO > KE N 2
*(C) KECO = KE N 2
(D) cannot be predicted unless volumes of the gases are given
11. The average kinetic energy of an ideal gas per molecule at 25°C is:
*(A) 6.17 x 10-21 J (B) 61.7 x 10-20 J (C) 6.17 x 10-10 J (D) 61.7 x 10-21 J
PHYSICAL CHEMISTRY /R # 04 E-1 /1
