At T (K) and pressure P, the diffusion rate of an ideal gas is 120 mL min . What is the time taken (in sec.) for 3000 mL of this gas for diffusion at the same temperature and pressure?
1
25
2
1500
3
250
4
150
Official Solution
Correct Option: (2)
The diffusion rate is directly proportional to the time taken for diffusion, given constant conditions for temperature and pressure. We know:
The time for 3000 mL of the gas to diffuse is: Converting to seconds: Thus, the time taken is .
02
PYQ 2023
easy
chemistryID: ap-eapce
A flask with open mouth containing air was heated from 27°C to 477°C. Some air was expelled. What is the fraction of air expelled out?
Official Solution
Correct Option: (1)
03
PYQ 2023
easy
chemistryID: ap-eapce
At 200 K, an ideal gas (X) present in a 1 L flask has a concentration of 1 mol . At the same temperature, 0.1 mole of X is added into the vessel. What is the final pressure of the gas in atm? (Given R = 0.082 L atm )
Official Solution
Correct Option: (1)
04
PYQ 2023
medium
chemistryID: ap-eapce
At T (K), an ideal gas (Z) present in V L flask exerted a pressure of 16.4 atm. Its concentration is 1 mol L . What is the value of T in K?
1
100
2
400
3
300
4
200
Official Solution
Correct Option: (4)
We use the ideal gas equation . Given:
05
PYQ 2023
medium
chemistryID: ap-eapce
An ideal gas (X) present in a vessel of volume exerted a pressure of 16.4 atm at 200 K. What is its concentration in mol ? Given Data Given
1
2
3
4
Official Solution
Correct Option: (3)
We can use the ideal gas law, which is given by: Where:
- is the pressure (16.4 atm)
- is the volume (given as L)
- is the number of moles
- is the ideal gas constant (0.082 L atm mol K )
- is the temperature (200 K) We can rewrite the equation to find the concentration ( ): Substitute the known values: Thus, the concentration of the gas is .
06
PYQ 2023
medium
chemistryID: ap-eapce
At 300 K, the following graph is obtained for one mole of an ideal gas. If its pressure is 10 atm, then its volume (in L) will be
1
0.11
2
1.1
3
2
4
4.0
Official Solution
Correct Option: (1)
From the graph, slope . Given , so:
07
PYQ 2023
medium
chemistryID: ap-eapce
A 100 L cylinder containing H2 exerted a pressure of 4 atm at 300 K. It was accidentally opened and some H2 was escaped. When it was closed, it exerted a pressure of 3 atm at 300 K. The number of moles of H2 remaining in the cylinder is equal to
1
2
3
4
Official Solution
Correct Option: (3)
Given the ideal gas law: Where:
- is pressure
- is volume
- is the number of moles
- is the gas constant
- is temperature At initial conditions:
Using the ideal gas law: So, the number of moles initially in the cylinder is: At final conditions:
Using the ideal gas law again: Thus, the number of moles remaining in the cylinder is: Since the volume and temperature remain constant, the ratio of the final to initial moles is: Thus, the number of moles remaining in the cylinder is .
08
PYQ 2023
medium
chemistryID: ap-eapce
At 300 K, the compressibility factor of 1 mole of a gas is 1.1. Its pressure is 2.706 atm. What is its volume in L? (Given R = 0.082 L atm mol K )
1
1
2
10
3
100
4
0.1
Official Solution
Correct Option: (2)
We can use the ideal gas law to solve for the volume: Given:
Substitute the values into the ideal gas law equation: So, the correct volume is approximately . Thus, the correct answer is .
09
PYQ 2023
medium
chemistryID: ap-eapce
The following data is obtained for one mole of a gas. The gas deviates from ideal behavior in the pressure (in bar) range
1
1 to 3
2
2 to 4
3
3.1 to 4.0
4
1 to 4
Official Solution
Correct Option: (3)
In the given data, the gas starts to deviate from ideal behavior at P = 3.1 bar and continues to deviate until P = 4.0 bar. The PV/RT values indicate ideal behavior up to P = 3.0 bar, but deviations are observed after that, starting from P = 3.1 bar.
10
PYQ 2023
medium
chemistryID: ap-eapce
At T (K), a closed vessel containing 2 g of an ideal gas (A) (molar mass = ) exerted a pressure of 1 atm. When 16 g of another ideal gas (B) (molar mass = ) was introduced into this vessel, the pressure increased to 2 atm. What is the correct relationship between and ?
1
2
3
4
Official Solution
Correct Option: (3)
Using the ideal gas law, the pressure is directly proportional to the amount of gas. Since the pressure doubled when 16 g of gas B was added, the relationship between the masses of A and B must satisfy .
11
PYQ 2025
medium
chemistryID: ap-eapce
A gas occupies 2 liters at a pressure of 3 atm. What will be its volume when the pressure is reduced to 1.5 atm at constant temperature?
1
2
3
4
Official Solution
Correct Option: (4)
Step 1: Recall Boyle's Law. Boyle's Law states that for a fixed amount of gas at constant temperature: where: = initial pressure = 3 atm = initial volume = 2 L = final pressure = 1.5 atm = final volume (to be found) Step 2: Rearrange the formula to solve for : Step 3: Plug in the known values:
