Principles Related to Practical Chemistry · Question 29

During Lassaigne's test, the elements present in an organic compound are converted from :

1. Ionic form to ionic form
2. Covalent form to ionic form
3. Ionic form to covalent form
4. Covalent form to covalent form

The functional group that can be identified through phthalein dye test is :

1. Carboxylic acid
2. Alcohol
3. Aldehyde
4. Phenolic

Phenolphthalein is used as an indicator for the titration of sodium hydroxide solution against a standard solution of oxalic acid. The colour change that is observed at an alkaline pH close to the equivalence point during this titration is :

1. pink to colourless
2. pinkish red to yellow
3. colourless to pink
4. yellow to pinkish red

Two products X and Y are formed in the following reaction sequence. [figure] The suitable method that can be used for the separation of products X and Y is :

1. Continuous extraction
2. Differential extraction
3. Sublimation
4. Fractional distillation

In a test tube containing a salt, a few drops of dilute H2SO4 was added, which gave colourless vapours having the smell of vinegar. The vapours turned the blue litmus paper red. Identify the correct anion from the following :

1. Carbonate, CO32-
2. Sulphide, S2-
3. Acetate, CH3COO-
4. Sulphate, SO42-

In potash alum, the ratio of K+ and SO42- ions is

1. 3 : 2
2. 1 : 2
3. 2 : 1
4. 2 : 3

Which one of the following reactions does NOT belong to "Lassaigne's test"?

1. Na + X NaX
2. 2CuO + C 2Cu + CO2
3. Na + C + N NaCN
4. 2Na + S Na2S

Match List-I with List-II Choose the correct answer from the options given below:

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

Match List-I with List-II Choose the correct answer from the options given below :

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

On heating, some solid substances change from solid to vapour state without passing through liquid state. The technique used for the purification of such solid substances based on the above principle is known as

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