Question

Vapour pressure of pure acetone and chloroform at 328 K are 741.8 mm Hg and 632.8 mm Hg 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 `chi_"acetone"`. The experimental data observed for different compositions of mixtures is:

`bb(100 xx chi_"acetone")`	`bb(P_"acetone"//"mm Hg")`	`bb(P_"chloroform"//"mm Hg")`
0	0	632.8
11.8	54.9	548.1
23.4	110.1	469.4
36.0	202.4	359.7
50.8	322.7	257.7
58.2	405.9	193.6
64.5	454.1	161.2
72.1	521.1	120.7

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

Answer 1

`bb(100 xx chi_"acetone")`	`bb(P_"acetone"//"mm Hg")`	`bb(P_"chloroform"//"mm Hg")`	Ptotal (mm Hg)
0	0	632.8	632.8
11.8	54.9	548.1	602.0
23.4	110.1	469.4	579.5
36	202.4	359.7	562.1
50.8	322.7	257.7	580.4
58.2	405.9	193.6	595.5
64.5	454.1	161.2	615.3
72.1	521.1	120.7	641.8

It can be observed from the graph that the plot for the P_total of the solution curves downward. Therefore, the solution shows a negative deviation from the ideal behaviour.