Final answer:
Helium (He) will take the least time to get out of a gas syringe because it has the lowest molar mass, and according to Graham's Law of Effusion, gases with lower molar masses effuse more quickly.
Step-by-step explanation:
The question asks which gas will take the least time to get out of a gas syringe among O₂ (oxygen), N₂ (nitrogen), Cl₂ (chlorine), and He (helium). The rate at which a gas will effuse (escape from a small opening such as a syringe) is given by Graham's Law of Effusion, which states that the rate of effusion of a gas is inversely proportional to the square root of its molar mass.
Comparing the molar mass of each gas:
- O₂: 32 g/mol
- N₂: 28 g/mol
- Cl₂: 71 g/mol
- He: 4 g/mol
Given the molar masses, helium (He) has the lowest molar mass and according to Graham's Law, helium will effuse more quickly than the other gases mentioned. Therefore, the correct answer is D) He.