The variation of vapour pressure (b) as a function of temperature (a) is studied for
` C_(2) H_(5) OC_(2)H_(5), C Cl_(4) " and " H_(2)O ` at 760 mm Hg and is shown in the figure below . The boiling temperatures of
` C_(2)H_(5) OC_(2) H_(5) . C Cl_(4) " and "H_(2)O ` are 308, 350 and 373 K respectively , Curves A,B,C respectively correspond to

Options

A. `H_(2)O, C_(2)H_(5)OC_(2)H_(5),C CL_(4)`
B. `C_(2)H_(5)OC_(2)H_(5),C Cl_(4),H_(2)O`
C. `C Cl_(4), C_(2) H_(5) OC_(2),H_(5),H_(2)O`
D. `C Cl_(4),H_(2)O,C_(2)H_(5) OC_(2)H_(5)`

Answer

C

Explanation

Given,
Boiling point (bp) at 760 mm of Hg for
(i) ` C_(2) H_ (5) OC_(2) H_(5) = 308 K `
(ii) ` C Cl_(4) = 350 K`
(iii) `H_(2)O = 373 K `
` because ` According to definition , the boiling point of a liquid is that temperature at which its vapour pressure becomes equal to the atmospheric pressure.
Now , weaker is the attractive force between the molecules of given species, more is its volatile nature and smaller is its boiling point , i.e.
attractive force ` prop (1)/("volatile ")` nature between the
molecules, volatile nature ` prop` vapour pressure over the liquid .
Temperature for boiling point ` prop (1)/("volatile ")` nature .
Now, drawing perpendicular on x-axis , i.e. on (a) from points B,A and C , we have
` T_(C) gt T_(A) gt T_(B)` .

Hence , (A) ` = C Cl_(4)`
(B) `= C_(2) H_(5) O C_(2) H_(5)`
(C) ` = H_(2) O`
Thus , option (c) is the correct answer .