Question

Vapour pressures of pure acetone and chloroform at $328K$ are $741.8mmHg$ and $632.8mmHg$ respectively. Assuming that they form ideal solution over the entire range of composition, plot $p_{total},p_{chloroform}$, and $p_{acetone}$ as a function of $x_{acetone}$. The experimental data observed for different compositions of mixture is:

$100x{x}_{acetone}$	$0$	$11.8$	$23.4$	$36.0$	$50.8$	$58.2$	$64.5$	$72.1$
$P_{acetone}/mmHg$	$0$	$54.9$	$110.1$	$202.4$	$322.7$	$405.9$	$454.1$	$521.1$
$P_{chloroform}/mmHg$	$632.8$	$548.1$	$469.4$	$359.7$	$257.7$	$193.6$	$161.2$	$120.7$

Plot this data also on the same graph paper. Indicate whether it has positive deviation or negative deviation from the ideal solution.

Answer 1

$x$ (acetone)	0	0.118	0.234	0.360	0.508	0.508	0.582	0.645 0.721
$P$ (acetone, mm Hg)	0	54.9	110.1	202.4	202.4	322.7	405.9	454.1 521.1
$P$ (chloroform, mm Hg)	632.8	548.1	469.4	359.7	359.7	257.7	193.6	151.2 120.7
$P$ (total)	632.8	603.0	579.5	562.1	562.1	580.4	599.5	615.3 641.8

The plot of $P$ (total) shows a dip downwards. This indicates negative deviation from ideal behaviour.