A liquid decomposes at its normal pressure. It can be purified by
Sublimation
Distillation
Filtration
Vacuum distillation
Camphor is often used in molecular weight determination because
It is volatile
It is readily available
Its cryoscopic constant is high
It is solvent for organic substances
An alkane has a C/H ratio (by mass) of 5.1428. Its molecular formula is
C5H12
C6H14
C8H18
C7H10
In an experiment, 0.1877g of an organic compound when analyzed by the Dumas method yielded 31.7 ml of moist nitrogen measured at 140C and 758 mm mercury pressure. The percentage of nitrogen in the compound is (Aqueous tension at 140C = 12 mm)
19.7
22.3
24.3
25.6
The latest technique for the purification of organic compounds is
Chromatography
Crystallization
Fractional distillation
If 0.183 g of an aromatic monobasic acid requires 15 ml of N/10 sodium hydroxide for complete neutralisation, then molecular weight of the acid is
56
122
166
224
When 0.759 g of the silver salt of dibasic organic acid was ignited, then a residue of 0.463 g of metallic silver was left. Molecular weight of the acid is
32
92
140
If 0.1 g of an organic compound containing phosphorus gave 0.222 g of Mg2P2O7 then the percentage of phosphorus in the compound is
0.2
31
62
66
If nitrogen and sulphur both are present in an organic compound, then during the Lassaigne’s test, both will change into
NaSCN
Na2S and NaCNO
Na2S and NaCN
Na2SO3 and NaCN
Which of the following method is used to estimate nitrogen in the laboratory ?
Carius method
Duma’s method
Liebig’s method
Kjeldahl’s method
