Question

A capillary tube of uniform diameter contains gas samples $A$ and $B$, separated by a short column of Hg, $l$ mm in length. The ends are sealed. In a horizontal position, the confined gases occupy $a$ mm and $b$ mm in length with a common unknown pressure ($P$). In vertical position (gas $A$ upward), the lengths become respectively $a$ mm and $b$ mm. The $P$ is equal to (in mm Hg):

• A. $\frac{l}{(\frac{a}{a^{\prime }}-\frac{b}{b^{\prime }})}$
• B. $l(\frac{a}{a^{\prime }}-\frac{b}{b^{\prime }})$
• C. $l(\frac{b}{b^{\prime }}-\frac{a}{a^{\prime }})$
• D. $\frac{l}{(\frac{b}{b^{\prime }}-\frac{a}{a^{\prime }})}$

Answer 1

By ideal gas law: $PV=nRT$
For a particular gas since $n$ and $T$ are constant. $\Rightarrow PV=Constant$