IISER Chemistry - Solutions
Exam Duration: 45 Mins Total Questions : 30
Which of the following solutions has the highest boiling point?
- (a)
0.1 M glucose
- (b)
0.1 M \(BaCl_2\)
- (c)
0.1 M NaCl
- (d)
0.1 Urea
The freezing point of the solution with increasing concentration of glucose will be as
- (a)
1%>2%>3%>10%
- (b)
10%>3%>2%>1%
- (c)
1%>2%>2%>10%
- (d)
10%>2%>3%>2%
10 g NaCl is dissolved in 10 g of the solution; its concentration, is
- (a)
1 ppm
- (b)
10 ppm
- (c)
100 ppm
- (d)
0.1 ppm
what is the mole fraction of water in a solution containing 1 mole of water in 4 moles of alcohol?
- (a)
0.2
- (b)
0.4
- (c)
0.6
- (d)
0.8
Molarity of a 15% solution of \(H_2SO_4\) ( destiny of \(H_2SO_4\)=1.10 g ml; given molecular wt=98) would be
- (a)
16.84 M
- (b)
1.684 M
- (c)
0.1684 M
- (d)
0.842 M
Molarity of 98% \(H_2SO_4\) having density 1.95 g ml would be (given molecular weight = 98) :
- (a)
16.0
- (b)
17.0
- (c)
18.0
- (d)
19.5
Of the given methods for molecular weight determination, in which case the sensitivity of the method decreases with increase in molecular weight of the solute
- (a)
viscosity measurement method
- (b)
dialysis method
- (c)
osmotic pressure measurement method
- (d)
elevation of boiling point method
2.46 g of NaOH are dissolved water and the solution is made 100 \(cm^3 \) in a volumetric flask. The molarity of the solution is
- (a)
0.165
- (b)
0.615
- (c)
0.325
- (d)
0.425
A X molal solution of a compound in benzene has mole fraction equal to 0.2. The molality of the solution is
- (a)
1.4
- (b)
2
- (c)
3.2
- (d)
14.0
50 g of methyl alcohol is added to 100 g of water. Mole fraction of methyl alcohol would be
- (a)
5.555
- (b)
1.5625
- (c)
0.2195
- (d)
1.2195
Vapour pressure of a solution of 5 g of non-volatile compound in 100 g of water at temperature T is 2985 N \(m^-2\). Vapour pressure of pure water is 3000 N \(m^-2\). The molecular weight of solute is
- (a)
60
- (b)
120
- (c)
180
- (d)
240
On mixing 20 ml of acetone with 60 ml chloroform, the total volume of the solution would be
- (a)
>80 ml
- (b)
<80 ml
- (c)
80 ml
- (d)
None of the above
Anhydrous \(CaCl_2\) is used to clear snowon roads in cold countries. Its function is to
- (a)
depress the freezing point of water
- (b)
increase the freezing point of water
- (c)
increase the temperature at which ice is expected to be formed
- (d)
nothing could be said
The benxene (v.p. = 268 mm) and ethylene chloride (v.p.= 236 mm) form ideal solution. The total pressure made by dissolving 2 moles benzene and 3 moles of ethyene chloide would be approximately
- (a)
249 mm
- (b)
255 mm
- (c)
270 mm
- (d)
504 mm
The vapour pressurre of a solvent decreased by 10 mm of Hg when a non-volatile solute was added to the solvent. The mole fraction of solute in solution is 0.2. What would be the mole fraction of solvent if decrease in vapour pressure is 20 mm of Hg?
- (a)
0.8
- (b)
0.6
- (c)
0.4
- (d)
0.2
The molal depression constant \(k_f\)of water is \(1.86^0 C\)34.2 g of sucrose and 12 g of Urea dissolved 1000 g of water, the freezing point of resultant solution would be
- (a)
\(-0.558^o C\)
- (b)
\(-2.8^O C\)
- (c)
\(-9.3^O C\)
- (d)
\(-1.86^O C\)
The molarity of 800 g of pure water is
- (a)
5.55 M
- (b)
55.5 M
- (c)
555 M
- (d)
NONE OF THESE
A substance will be deliquecent if its vapour pressure is
- (a)
equal to the atmospheric pressure
- (b)
less than that of water vapour in air
- (c)
equal to that of water of vapour in air
- (d)
greater than that of water vapour in air
An azeotropic solution of two liquids has boiling point lower than either of them when it
- (a)
is saturaated
- (b)
shows +ve deviation from Raoult's low
- (c)
shows -ve devitions from Raoult's low
- (d)
shows no deviation from Raoult's law
The mole fraction of water in a mixture of 12.0 g water, 108 g acetic acid and 92 g ethyl alcohol would be
- (a)
1.149
- (b)
0.1493
- (c)
2.149
- (d)
0.2493
How many grams of H2SO4 is to be dissolved to prepare 200 mL aqueous solution having concentration of H3O+ ions is 1 M at 25o C temperature ?
- (a)
19.6 g
- (b)
0.98 g
- (c)
4.9 g
- (d)
9.8 g
What is the molality of a solution in which 18 g glucose (mol. wt. =180) is dissolved in 500 g of H2O?
- (a)
0.5 m
- (b)
0.2 m
- (c)
2 m
- (d)
1 m
Normality of 2 M H2SO4 is
- (a)
4N
- (b)
6N
- (c)
\(\frac { N }{ 4 } \)
- (d)
\(\frac { N }{ 6 } \)
Vapour pressure of pure'A' is 70 mm of Hg at 25o C. If it forms an ideal solution with 'B' in which mole fraction of A is 0.8 and vapour pressure of the solution is 84 mm of Hg at 25o C, then the vapour pressure of pure 'B' at 25o C is
- (a)
140 mm
- (b)
70 mm
- (c)
56 mm
- (d)
28 mm
Low concentration of oxygen in the blood and tissues of people living at high altitude is due to
- (a)
low temperature
- (b)
low atmospheric pressure
- (c)
high atmospheric pressure
- (d)
both low temperature and high atmospheric pressure
Which of the following statements is false?
- (a)
Units of atmospheric pressure and osmotic pressure are the same
- (b)
In reverse osmosis, solvent molecules move through a semipermeable membrane from a region of lower concentration of solute to a region of higher concentration.
- (c)
The value of molal depression constant depends upon the nature of solvent
- (d)
relative lowering of vapour pressure is a dimensionless quantity
Isotonic solution must have the same
- (a)
solute
- (b)
density
- (c)
mass
- (d)
depression in freezing point
The density of a solution prepared by dissolving 120 g of urea (mol. mass = 604) in 1000 g of water is 1.15 g/mL. The molarity of the solution is
- (a)
0.50 M
- (b)
1.78 M
- (c)
1.02 M
- (d)
2.05 M
Ethylene glycol is used as an antifreeze in a cold climate. Mass of ethylene glycol which should be added to 4 kg of water to prevent it from freezing at water to prevent it from freezing at -6o C will be (Kf for water = 1.86 K kg mol-1 and molar mass of ethylene glycol = 62 mol-1)
- (a)
800.00 g
- (b)
204.30 g
- (c)
400.00 g
- (d)
304.60 g
On mixing heptane and octane form an ideal solution, at 373 K, the vapour pressures of the two liquid components (heptane and octane) are 105 kPa and 45 kPa, respectively. Vapour pressure of the solution obtained by mixing 25 g of heptane and 35 g of octane will be (molar mass of heptane = 100 g mol-1 and that of octane = 114 g mol-1)
- (a)
72.0 kPa
- (b)
36.1 kPa
- (c)
96.2 kPa
- (d)
144.5 kPa