Question

Two flasks X and Y, each of 500 $mL$ capacity contain hydrogen and helium respectively at 27${}^{o}C$ and 1 atmospheric pressure. Flask X contains:

• A. the same number of atoms as in Y
• B. the same weight of the gas as in Y
• C. half the number of atoms as in Y
• D. double the number of atoms as in Y

Answer 1

The correct option is D double the number of atoms as in Y

Since volume, pressure, and temperature all are same for both the gases, we get that moles will also be the same (because $PV=nRT$).

So, $\frac{n_1}{N}=\frac{n_2}{N}$

where $n$ represents the number of molecules and $N$ represents the Avogadro's number.

Now each hydrogen molecule has 2 atoms. So, the flask containing hydrogen will have double the atoms as that of the helium flask.

Hence, the correct answer is option $\text{D}$.