# Gaseous state mcq with answers 2023

Practice Gaseous state MCQs questions with answers for IITJAM, CSIR-NET and other Msc level entrace exam. You can also check other IIT-JAM questions for free.

1. A gas occupies 100.0 mL at 50°C and 1 atm pressure. The gas is cooled at constant pressure so that volume is reduced to 50.0 mL. What is the final temperature:

(a) -111.5°C
(b) 111.5°C
(c) 111.5 K
(d) 384 K

2. If the temp. of a particular amount of gas is increased from 27°C to 57°C, find final volume of the gas, if initial volume = 1L and assume pressure is constant.

(a) 1.0L
(b) 1.1 L
(c) 0.9L
(d) 2 L

3. If the pressure of a gas contained in a closed vessel is increased by 0.4 % when heated by 1°C its initial temperature must be :

(a) 250 K
(b) 250°C
(c) 25°C
(d) 25 K

4. Four one litre flasks are separately filled with the gases, O2, F2, CH4 and CO2 under the same conditions. The ratio of number of molecules in these gases:

(a) 2 : 2 : 4 : 3
(b) 1 : 1 : 1 : 1
(c) 1 : 2 : 3 : 4
(d) 2 : 2 : 3 : 4

5. Which of the following curve does not shows a linear variation (slope either +ve or -ve)?

(a) P  v/s  1/V
(b) log P  v/s  log V
(C) P/V  v/s  1/V2
(d) P/V  v/s  V2

6. The density of gas A is twice that of B at the same temperature the molecular weight of gas B is thrice that of A. The ratio of pressure of gas A and gas B will be

(a) 1 : 6
(b) 7 : 8
(c) 6 : 1
(d) 1 : 4

7. The density of a mixture of O2 and N2 at NTP is 1.3 g litre-1. What is the partial pressure of N2

(a) 1.725 atm
(b) 0.725 atm
(C) 0.593 atm
(d) 1.593 atm

8. A 11 litre flask contains 20g of neon and an unknown weight of hydrogen. The gas density is found to be 2g/litre at 0°C. What is the average molecular weight?

(a) 11
(b) 12
(c) 13
(d) 10

9. A and B are two identical vessels. A contains 15 g ethane at latm and 298 K. The vessel B contains 75 g of a gas X at same temperature and pressure. The vapour density of X is :

(a) 75
(b) 150
(c) 37.5
(d) 45

10. A mixture of hydrogen and oxygen at one bar pressure contains 20% by weight of hydrogen. Partial pressure of hydrogen will be

(a) 0.2 bar
(b) 0.4 bar
(c) 0.6 bar
(d) 0.8 bar

11. 2 moles of NH3 & 1 mol of HCl are kept in 8.21 L container. The temperature is 300 K. Calculate the final pressure after the reaction. Given NH4Cl is solid.

(a) 0.5 atm
(b) 1 atm
(c) 2 atm
(d) 4 atm

12. The partial pressure of hydrogen in a flask containing two grams of hydrogen and 32 gm of sulphur dioxide is :

(a) 1/16th of the total pressure
(b) 1/9th of the total pressure
(c) 2/3th of the total pressure
(d) 1/8th of the total pressure

13. What is the value of total K.E. of 0.5 mol of an ideal gas at 273 K

(a) 1702 J
(b) 1803 J
(c) 2053 J
(d) 1930 J

14. The ratio between the r.m.s. velocity of H2 at 50 K and that of O2  at 800 K is

(a) 4
(b) 2
(c) 1
(d) 1/4

15. At what temperature K.E. of a gas molecules is half of its value at 327°C?

(a) 13.5°C
(b) 150°C
(c) 27°C
(d) -123°C

16. Which statement is correct?

(a) K.E. of molecules is highest in solid state
(b) P.E. is lowest in solid state
(c) K.E..of molecules is highest in gaseous state
(d) Torr is a unit of temperature

17. Most probable speed, average speed and RMS speed are related as :-

(a) 1 : 1.28 : 1.224
(b) 1 : 1.28 : 1.424
(c) 1 : 1.128 : 1.224
(d) 1 : 1.428 : 1.442

18. Helium atom is two times heavier than a hydrogen molecule. At 298 K, the average kinetic energy of a lielium atom

(a) two times that of a hydrogen molecule
(b) same as that of a hydrogen molecule
(c) four times that of a hydrogen molecule
(d) half that of a hydrogen molecule

19. According to the kinetic theory of gases, for a diatomic molecule

(a) the pressure exerted by the gas is proportional to the mean speed of the molecules
(b) the pressure exerted by the gas is proportional to the root mean square speed of the molecules
(c) the root mean square speed of the molecules is inversely proportional to the temperature
(d) the mean translation kinetic energy of the molecules is proportional to the absolute temperature

20. If a gas is allowed to expand at constant temperature then which of the following does hold true:

(a) the kinetic energy of the gas molecules decreases
(b) the kinetic energy of the gas molecules increases
(c) gas molecules remains the same
(d) Can not be predicted