Dalton's law

Dalton's law stablishes that the partial pressure of a gas $i$ in a ideal mixture of gases at pressure $P$ is:

$P_{i}=X_{i}\,P$

where Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle X_{i}} is the molar fraction of a gas $i$.