Principles Related to Practical Chemistry

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

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

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.

Which among the following purification methods is based on the principle of "Solubility" in two different solvents?

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

In chromyl chloride test for confirmation of Cl- ion, a yellow solution is obtained. Acidification of the solution and addition of amyl alcohol and 10\% H2O2 turns organic layer blue indicating formation of chromium pentoxide. The oxidation state of chromium in that is

1. +6
2. +5
3. +3
4. +10

Appearance of blood red colour, on treatment of the sodium fusion extract of an organic compound with FeSO4 in presence of concentrated H2SO4 indicates the presence of element/s

1. Br
2. S
3. N and S
4. N

On passing a gas, 'X', through Nessler's reagent, a brown precipitate is obtained. The gas 'X' is

1. Cl2
2. CO2
3. NH3
4. H2S

Chromatographic technique/s based on the principle of differential adsorption is / are Choose the most appropriate answer from the options given below:

1. B only
2. A only
3. A & B only
4. C only

A reagent which gives brilliant red precipitate with Nickel ions in basic medium is

1. dimethyl glyoxime
2. sodium nitroprusside
3. meta-dinitrobenzene
4. neutral FeCl3

Yellow compound of lead chromate gets dissolved on treatment with hot NaOH solution. The product of lead formed is a :

1. Tetraanionic complex with coordination number six
2. Neutral complex with coordination number four
3. Dianionic complex with coordination number six
4. Dianionic complex with coordination number four

NaCl reacts with conc. H2SO4 and K2Cr2O7 to give reddish fumes (B), which react with NaOH to give yellow solution (C). (B) and (C) respectively are ;

1. CrO2Cl2, Na2CrO4
2. Na2CrO4, CrO2Cl2
3. CrO2Cl2, KHSO4
4. CrO2Cl2, Na2Cr2O7

The technique used for purification of steam volatile water immiscible substances is :

1. Fractional distillation
2. Distillation
3. Fractional distillation under reduced pressure
4. Steam distillation

Phenolic group can be identified by a positive:

1. Tollen's test
2. Phthalein dye test
3. Carbylamine test
4. Lucas test