# Problem: Carbon tetrachloride, CCl 4, has a vapor pressure of 213 torr at 40. ˚C and 836 torr at 80. ˚C. What is the normal boiling point of CCl4?

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###### FREE Expert Solution

Clausius-Clapeyron Equation:

$\overline{){\mathbf{ln}}\frac{{\mathbf{P}}_{\mathbf{2}}}{{\mathbf{P}}_{\mathbf{1}}}{\mathbf{=}}{\mathbf{-}}\frac{\mathbf{∆}{\mathbf{H}}_{\mathbf{vap}}}{\mathbf{R}}\mathbf{\left[}\frac{\mathbf{1}}{{\mathbf{T}}_{\mathbf{2}}}\mathbf{-}\frac{\mathbf{1}}{{\mathbf{T}}_{\mathbf{1}}}\mathbf{\right]}}$

Solve for ΔHvap:

${\mathbf{ln}}\left(3.92\right){\mathbf{=}}{\mathbf{-}}\frac{\mathbf{∆}{\mathbf{H}}_{\mathbf{vap}}}{\mathbf{8}\mathbf{.}\mathbf{314}\frac{\mathbf{J}}{\mathbf{mol}}}\mathbf{\left[}\mathbf{-}\mathbf{3}\mathbf{.}\mathbf{62}\mathbf{×}{\mathbf{10}}^{\mathbf{-}\mathbf{4}}\mathbf{\right]}\phantom{\rule{0ex}{0ex}}\phantom{\rule{0ex}{0ex}}\phantom{\rule{0ex}{0ex}}{\mathbf{1}}{\mathbf{.}}{\mathbf{366}}\left(8.314\frac{J}{\mathrm{mol}}\right){\mathbf{=}}\overline{)\mathbf{-}}\frac{\mathbf{∆}{\mathbf{H}}_{\mathbf{vap}}}{\overline{)\mathbf{8}\mathbf{.}\mathbf{314}\frac{J}{\mathrm{mol}}}}\mathbf{\left[}\overline{)\mathbf{-}}\mathbf{3}\mathbf{.}\mathbf{62}\mathbf{×}{\mathbf{10}}^{\mathbf{-}\mathbf{4}}\mathbf{\right]}\left(\overline{)8.314\frac{J}{\mathrm{mol}}}\right)$ ###### Problem Details

Carbon tetrachloride, CCl 4, has a vapor pressure of 213 torr at 40. ˚C and 836 torr at 80. ˚C. What is the normal boiling point of CCl4?