18 g glucose (C6H12O6 ) is added to 178.2 g water. The vapor pressure of water (in torr) for this aqueous solution is:
76.0
752.4
759.0
759.0
B.
752.4
Vapour pressure of water (p°) = 760 torr
Number of moles of glucose
Molar mass of water = 18 g/mol
Mass of water (given) = 178.2 g
Number of moles of water
Total number of moles = (0.1 +9.9) = 10 moles
Now, the mole fraction of glucose in solution = Change in pressure with respect to initial pressure.
therefore, Vapour pressure of solution = (760-7.6)torr
=752.4 torr
The vapour pressure of acetone at 20oC is 185 torr. When 1.2 g of a non-volatile substance was dissolved in 100 g of acetone at 20oC, its vapour pressure was 183 torr. The molar mass (g mol-1 ) of the substance is:
32
64
128
128
3 g of activated charcoal was added to 50 mL of acetic acid solution (0.06N) in a flask. After an hour it was filtered and the strength of the filtrate was found to be 0.042 N. The amount of acetic acid adsorbed (per gram of charcoal) is:
18 mg
36 mg
42 mg
42 mg
For the estimation of nitrogen 1.4g of an organic compound was digested by Kjeldahl's method and the evolved ammonia was absorbed in 60 mL of M/10 sulphuric acid. The unreacted acid required 20 mL of M/10 sodium hydroxide for complete neutralisation. The percentage of nitrogen in the compound is
6%
10%
3%
3%
Consider separate solution of 0.500 M C2H5OH (aq), 0.100 M Mg3(PO4)2 (aq) 0.250 M KBr (aq) and 0.125 M Na3PO4 (aq) at 25oC. Which statement is true about these solutions, assuming all salts to be strong electrolytes?
They all have the same osmotic pressure
0.100 M Mg3(PO4)2 (aq) has the highest osmotic pressure
0.125 M Na3PO (aq) has the highest osmotic pressure
0.125 M Na3PO (aq) has the highest osmotic pressure
The ratio of masses of oxygen and nitrogen of a particular gaseous mixture is 1:4. The ratio of number of their molecule is
1:4
7:32
1:8
1:8
The molarity of a solution obtained by mixing 750 mL of 0.5 (M) HCl with 250 mL of 2(M) HCl will be
0.875 M
1.00 M
1.75 M
1.75 M
The density of a solution prepared by dissolving 120 g of urea (mol. Mass = 60 u ) in 1000g of water is 1.15 g/mL. The molarity of this solution is
0.50 M
1.78 M
1.02 M
1.02 M
Kf for water is 1.86K kg mol–1.If your automobile radiator holds 1.0 kg of water, how many grams of ethylene glycol (C2H6O2) must you add to get the freezing point of the solution lowered to –2.8°C?
72 g
93 g
39 g
39 g
A 5.2 molal aqueous solution of methyl alcohol, CH3OH, is supplied. What is the mole fraction of methyl alcohol in the solution?
0.100
0.190
0.086
0.086