Question

At STP, 2 moles of hydrogen can occupy how much volume in litres?
[A] 11.2
[B] 22.4
[C] 33.6
[D] 44.8
[E] 67.2

Answer 1

HINT: You should know that STP is the standard temperature and pressure set by the IUPAC. To answer this question you have to approach using the STP rule set up regarding the molar volume of a gas.

COMPLETE STEP BY STEP SOLUTION: We know that standard temperature and pressure is abbreviated as STP. It is the standard set of conditions which are set up for the experimental measurement and it allows us to establish and compare different sets of data.
The STP is set by IUPAC however the standard temperature and pressure used by NIST is different than that of the IUPAC. But, both of these are accepted worldwide.
Now, in the question we have been asked to find the volume occupied by 2 moles of hydrogen gas.
According to STP, the molar volume of a gas is the volume of one mole of a gas. At STP, one mole of any gas occupies 22.4 litres of volume. One mole of a gas is given by the Avogadro’s number i.e. ${{N}_{A}}$ and it is given as $6.023\times {{10}^{23}}$.
According to this, one mole of hydrogen gas at STP will occupy 22.4 L of volume. Therefore, 2 moles of hydrogen gas will occupy a volume twice of 22.4 L i.e. 44.8 L.
So, we can see from the above discussion that 2 moles of hydrogen gas occupies 44.8L volume.

Therefore, the correct answer is option [D] 44.8.

NOTE: We should not be confused between NTP and STP. NTP is normal temperature and pressure whereas STP is standard temperature and pressure. STP is set by IUPAC which is the International Union of Pure and Applied Chemistry as ${{0}^{{}^\circ }}$ Celsius and 100 kPa or 1 bar. NTP is set as 101.325 kPa and ${{20}^{{}^\circ }}$ Celsius temperature.