At 25°C, at 5% aqueous solution of glucose (molecular weight = 180g mol-1) is isotonic with a 2% aqueous solution containing and unknown solute. What is the molecular weight of the unknown solute?
60
80
72
63
200 mL of water is added to a 500 mL of 0.2 M solution. What is the molarity of this diluted solution?
0.5010M
0.2897M
0.7093
0.1428
Which of the following pairs of substances would give same gaseous product on reaction with water?
Na and Na2O2
Ca and CaH2
Ca and CaO
Ba and BaO2
When 200 mL of aqueous solution of HCl (pH = 2) is mixed with 300 mL of an aqueous solution of NaOH (pH = 12) the pH of the resulting mixture is
10
2.7
4.0
11.3
In acid medium, Zn reduces nitrate ion to NH ion according to the reaction,
Zn + NO→ Zn2+ + NH + H2O (unbalanced).
How many moles of HCl are required to reduce half a mole of NaNO3 completely ? Assume the availability of sufficient Zn.
5
4
3
2
The percentage of an element M is 53 in its oxide of molecular formula M2O3. Its atomic mass is about
45
9
27
36
The relative lowering of vapour pressure of a dilute aqueous solution containing non-volatile solute is 0.0125. The molality of the solution is about
0.70
0.50
0.90
0.80
A.
0.70
Relative lowering of vapour pressure = mole fraction of solute (Raoult's Law)
where, w = weight of solute
M = molecular weight of solvent
m = molecular weight of solute
W = weight of solvent
0.0125 =
or, = 0.00070
Hence, molarity =
= 0.0007 × 1000
= 0.70
The pH of a solution obtained by mixing 50 mL of 1 N HCl and 30 mL of 1 N NaOH is [log 2.5 = 0.3979]
12.042
0.6021
0.3979
3.979
0.1 mole of a carbohydrate with empirical formula CH2O contains 1 g of hydrogen. What is its molecular formula?
C2H4O2
C5H10O5
C3H6O3
C6H12O6
How much of sulphur is present in an organic compound, if 0.53 g of the compound gave 1.158 g of BaSO4 on analysis ?
10%
20%
30%
15%