1
IIT-JEE 2000
Subjective
+3
-0
To 500 cm3 of water, 3.0 $$\times$$ 10-3 kg of acetic acid is added. If 23% of acetic acid is dissociated, what will be the depression in freezing point? Kf and density of water are 1.86 K kg-1 mol-1 and 0.997 g cm-3, respectively
2
IIT-JEE 1999
Subjective
+10
-0
Nitrobenzene is formed as the major product along with a minor product in the reaction of benzene with a hot mixture of nitric acid and sulphuric acid. The minor product consists of carbon : 42.86 %, hydrogen : 2.40%, nitrogen : 16.67% and oxygen : 38.07% (i) Calculate the empirical formula of the minor product. (ii) When 5.5 g of the minor product is dissolved in 45 g of benzene, the boiling point of the solution is 1.84 oC higher than that of pure benzene. Calculate the molar mass of the minor product and determine its molecular and structural formula. (Molal boiling point elevation constant of benzene is 2.53 K kg mol-1)
3
IIT-JEE 1998
Subjective
+4
-0
A solution of a nonvolatile solute in water freezes at -0.30oC. The vapour pressure of pure water at 298 K s 23.51 mm Hg and Kf for water is 1.86 K kg mol-1. Calculate the vapour pressure of this solution at 298 K.
4
IIT-JEE 1996
Subjective
+3
-0
The molar volume of liquid benzene (density = 0.877 g mL-1) increases by a factor of 2750 as it vaporises at 20oC and that of liquid toluene (density = 0.867 g mL-1) increases by a factor of 7720 at 20oC. A solution of benzene and toluene at 20oC has vapour pressure of 46.0 Torr. Find the mole fraction of benzene in the vapour above the solution.
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