Kinetic Theory - Result Question 19
19. Three containers of the same volume contain three different gases. The masses of the molecules are $m_1, m_2$ and $m_3$ and the number of molecules in their respective containers are $N_1$, $N_2$ and $N_3$. The gas pressure in the containers are $P_1, P_2$ and $P_3$ respectively. All the gases are now mixed and put in one of these containers. The pressure $P$ of the mixture will be
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(a) $P<(P_1+P_2+P_3)$
(b) $P=\frac{P_1+P_2+P_3}{3}$
(c) $P=P_1+P_2+P_3$
(d) $P>(P_1+P_2+P_3)$
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Answer:
Correct Answer: 19. (c)
Solution:
- (c) According to Dalton’s law of partial pressures, we have $P=P_1+P_2+P_3$
Dalton’s law will be valid only if the gases contained are non reacting.
For $n$ non-reacting gases, $P=P_1+P_2+P_3+\ldots P_n$ Here $P=$ Pressure exerted by mixture $P_1, P_2, P_3 \ldots . . P_n=$ Partial pressure of component gas.
