A solution made by dissolving 40 g NaOH in 1000 g of H2O is
1 molar
1 normal
1 molal
None of these
A 0.5 g/L solution of glucose is found to be isotonic with a 2.5 g/L solution of an organic compound. What will be the molecular weight of that organic compound ?
300
600
900
200
The mass of carbon anode consumed (giving only carbondioxide) in the production of 270 kg of aluminium metal from bauxite by the Hall process is (Atomic mass Al= 27)
180 kg
270 kg
540 kg
90 kg
D.
90 kg
In Hall and Heroult process
2Al2O3 4Al + 3O2
4C + 3O2 2CO2 + 2CO
2Al2O3 + 4C 4Al + 2CO2 + 2CO
Only for removal of CO2, following equation is possible
2Al2O3 + 3C 4Al + 3CO2
Molecular weight of Carbon = 12
Molecular weight of Aluminium = 27
For Carbon/ C = 3 x 12 = 36
For Aluminium/ Al = 4 x 27 = 108
For 108 gm of Al, 36 gm of C is required in above reaction
For 270 gm of Al require amount of C =
The number of moles of KMnO4 reduced by one mole of KI in alkaline medium is
one-fifth
five
one
two
A solution has a 1 : 4 mole ratio of pentane to hexane. The vapour pressure of the pure hydrocarbons at 20C are 440 mm of Hg for pentane and 120 mm of Hg for hexane. The mole fraction of pentane in the vapour phase would be
0.549
0.200
0. 786
0.478
If for a sucrose solution, elevation in boiling point is 0.1°C, then what will be the boiling point of NaCl solution for same molal concentration ?
0.1C
0.2C
0.08C
0.01C
The vapour pressure of pure water is 25.0 mm Hg and that of an aqueous dilute solution of urea in 20mm Hg at 25°C. The molarity of the solution is:
12.6
14.9
13.8
9.6
The significant figures in 1.0024, 1.240 and 0.0020 are respectively
5, 4, 2
3, 3, 1
5, 3, 4
5, 3, 2