Principles Related to Practical Chemistry

Lassaigne's test is used for detection of :

1. Phosphorous and halogens only
2. Nitrogen, Sulphur and Phosphorous only
3. Nitrogen, Sulphur, phosphorous and halogens
4. Nitrogen and Sulphur only

Following Kjeldahl's method, 1 g of organic compound released ammonia, that neutralised 10 mL of 2 M H2SO4. The percentage of nitrogen in the compound is %.

The compound that is white in color is

1. ammonium sulphide
2. ammonium arsenomolybdate
3. lead iodide
4. lead sulphate

Match List I with List II

1. A-I, B-II, C-IV, D-III
2. A-II, B-III, C-I, D-IV
3. A-IV, B-I, C-II, D-III
4. A-IV, B-III, C-II, D-I

'Adsorption' principle is used for which of the following purification method?

1. Chromatography
2. Sublimation
3. Distillation
4. Extraction

Molar mass of the salt from NaBr, NaNO3, KI and CaF2 which does not evolve coloured vapours on heating with concentrated H2SO4 is g mol-1. (Molar mass in g mol-1 : Na : 23, N : 14, K : 39, O : 16, Br : 80, I : 127, F : 19, Ca : 40)

The fragrance of flowers is due to the presence of some steam volatile organic compounds called essential oils. These are generally insoluble in water at room temperature but are miscible with water vapour in vapour phase. A suitable method for the extraction of these oils from the flowers is -

1. distillation
2. steam distillation
3. distillation under reduced pressure
4. crystallisation

Given below are two statements : In the light of the above statements, choose the most appropriate answer from the options given below :

1. Both Statement I and Statement II are false
2. Statement I is true but Statement II is false
3. Both Statement I and Statement II are true
4. Statement I is false but Statement II is true

The Lassaigne's extract is boiled with dil HNO3 before testing for halogens because,

1. Silver halides are soluble in HNO3.
2. AgCN is soluble in HNO3.
3. Na2S and NaCN are decomposed by HNO3.
4. Ag2S is soluble in HNO3.

On a thin layer chromatographic plate, an organic compound moved by 3.5 cm, while the solvent moved by 5 cm. The retardation factor of the organic compound is 10-1.