JEE Purification & Characterisation PYQs With Video Solutions PDF

0.8 g of an organic compound was analysed by Kjeldahl's method for the estimation of nitrogen. If the percentage of nitrogen in the compound was found to be 42%, then _________ mL of 1M H$$_2$$SO$$_4$$ would have been neutralized by the ammonia evolved during the analysis.

Consider two chemical reactions (A) and (B) that take place during metallurgical process:
(A) ZnCO$$_{3(s)} \xrightarrow{\Delta}$$ ZnO$$_{(s)}$$ + CO$$_{2(g)}$$
(B) 2ZnS$$_{(s)}$$ + 3O$$_{2(g)} \xrightarrow{\Delta}$$ 2ZnO$$_{(s)}$$ + 2SO$$_{2(g)}$$
The correct option of names given to them respectively is:

Which of the following compound is added to the sodium extract before addition of silver nitrate for testing of halogens?

Which one of the following techniques is not used to spot components of a mixture separated on thin layer chromatographic plate?

Compound that will give positive Lassaigne's test for both nitrogen and halogen is

Match List I with List II: LIST I (Technique): A. Distillation B. Fractional distillation C. Steam distillation D. Distillation under reduced pressure. LIST II (Application): I. Separation of glycerol from spent-lye II. Aniline - Water mixture III. Separation of crude oil fractions IV. Chloroform-Aniline. Choose the correct answer from the options given below:

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 the vapour phase. A suitable method for the extraction of these oils from the flowers is:

In sulphur estimation. 0.471 g of an organic compound gave 1.4439 g of barium sulphate. The percentage of sulphur in the compound is _____ (Nearest Integer)
(Given: Atomic mass Ba: 137u, S: 32u, O: 16u)

Given below are two statements:
Statement I: Griss-Ilosvay test is used for the detection of nitrite ion, which involves the use of sulphanilic acid and $$\alpha-naphthylamine$$ reagent.
Statement II: In the above test, sulphanilic acid is diazotized by the acidified nitrite ion, which on further coupling with $$\alpha-naphthylamine$$ forms an azo-dye.
In the light of the above statements, choose the correct answer from the options given below

Question Stem (Q17 & Q18): Consider the following reaction sequence in which J , K , L and M are the major products.

1,3-dimethylbenzene ($$m$$-xylene) $$\xrightarrow[\text{3. sodium 3-nitrophenoxide (}\mathrm{NaO}\text{-}\mathrm{C_6H_4}\text{-}\mathrm{NO_2}\text{)}]{\text{1. } \mathrm{ClCH_2COCl},\ \text{anhyd. } \mathrm{AlCl_3}\quad\text{2. NaI, heat}} \mathbf{J} \xrightarrow[\text{2. } \mathrm{PBr_3}]{\text{1. } \mathrm{NaBH_4}} \mathbf{K}\ (\text{molar mass } 350\ \mathrm{g/mol})$$

$$\mathbf{K} \xrightarrow{\mathrm{NH_3}\ (\text{excess})} \mathbf{L}\ (\text{nitrogen containing compound})$$

$$\mathbf{K} \xrightarrow{\mathrm{PhSNa}} \mathbf{M}\ (\text{sulphur containing compound})$$

Given: Atomic mass (in amu): H : 1, C : 12, N : 14, O : 16, S : 32, Br : 80, Ba : 137

The volume of 1 M aqueous $$\mathrm{H_2SO_4}$$ required to completely neutralize the ammonia evolved from 5.72 g of L in Kjeldahl's method of nitrogen estimation is ___ mL.

Question Stem (Q17 & Q18): Consider the following reaction sequence in which J , K , L and M are the major products.

1,3-dimethylbenzene ($$m$$-xylene) $$\xrightarrow[\text{3. sodium 3-nitrophenoxide (}\mathrm{NaO}\text{-}\mathrm{C_6H_4}\text{-}\mathrm{NO_2}\text{)}]{\text{1. } \mathrm{ClCH_2COCl},\ \text{anhyd. } \mathrm{AlCl_3}\quad\text{2. NaI, heat}} \mathbf{J} \xrightarrow[\text{2. } \mathrm{PBr_3}]{\text{1. } \mathrm{NaBH_4}} \mathbf{K}\ (\text{molar mass } 350\ \mathrm{g/mol})$$

$$\mathbf{K} \xrightarrow{\mathrm{NH_3}\ (\text{excess})} \mathbf{L}\ (\text{nitrogen containing compound})$$

$$\mathbf{K} \xrightarrow{\mathrm{PhSNa}} \mathbf{M}\ (\text{sulphur containing compound})$$

Given: Atomic mass (in amu): H : 1, C : 12, N : 14, O : 16, S : 32, Br : 80, Ba : 137

In sulphur estimation by Carius method, the amount of $$\mathrm{BaSO_4}$$ formed from 3.79 g of M is ___ g.

0.1 mol of the following given antiviral compound (P) will weigh _______ $$\times 10^{-1}$$ g.

(Given: molar mass in g mol$$^{-1}$$ H: 1, C: 12, N: 14, O: 16, F: 19, I: 127)

During estimation of nitrogen by Dumas' method of compound X (0.42 g) :

_________ mL of $$N_2$$ gas will be liberated at STP. (nearest integer)
(Given molar mass in g mol$$^{-1}$$ : C : 12, H : 1, N : 14)

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

Given below are two statements :
Statement I : A mixture of C$$_{12}$$H$$_{22}$$O$$_{11}$$ (sugar) and NaCl can be separated by dissolving sugar in alcohol, due to differential solubility.
Statement II : Rose essence from rose petals is separated by steam distillation due to its high volatility and insolubility in H$$_2$$O.
In the light of the above statements, choose the correct answer from the options given below :

The principle of column chromatography is:

Which method of purification is used when the difference in the boiling points of two liquids is low (<25K)?

Copper wire test for halogens is known as

On a thin layer chromatographic plate, an organic compound moved by $$3.5 \text{ cm}$$, while the solvent moved by $$5 \text{ cm}$$. The retardation factor of the organic compound is ____________ $$\times 10^{-1}$$.

Chromatographic technique/s based on the principle of differential adsorption is/are
A. Column chromatography B. Thin layer chromatography C. Paper chromatography
Choose the most appropriate answer from the options given below:

1.4 g of an organic compound was digested according to Kjeldahl's method and the ammonia evolved was absorbed in 60 mL of M/10 $$H_2SO_4$$ solution. The excess sulphuric acid required 20 mL of M/10 NaOH solution for neutralization. The percentage of nitrogen in the compound is:

Question Stem (Q17 & Q18): Consider the following reaction sequence in which J , K , L and M are the major products.

Given: Atomic mass (in amu): H : 1, C : 12, N : 14, O : 16, S : 32, Br : 80, Ba : 137

The volume of 1 M aqueous $$\mathrm{H_2SO_4}$$ required to completely neutralize the ammonia evolved from 5.72 g of L in Kjeldahl's method of nitrogen estimation is ___ mL.

The ammonia evolved from the treatment of $$0.30$$ g of an organic compound for the estimation of nitrogen was passed in $$100$$ mL of $$0.1$$ M sulphuric acid. The excess of acid required $$20$$ mL of $$0.5$$ M sodium hydroxide solution for complete neutralization. The organic compound is

Match the organic compounds in column - I with the Lassaigne's test result in column - II appropriately:

Column - I                                   Column - II
A. Aniline                                i. Red colour with FeCl$$_3$$
B. Benzene sulfonic acid     ii. Violet color with sodium nitroprusside
C. Thiourea                            iii. Blue color with acidic solution of FeSO$$_4$$

The correct match between items of List-I and List-II is
List - I                                                                           List - II
(A) Coloured impurity                                                (P) Steam distillation
(B) Mixture of o-nitrophenol and p-nitrophenol (Q) Fractional distillation
(C) Crude Naphtha                                                    (R) Charcoal treatment
(D) Mixture of glycerol and sugars                              (S) Distillation under reduced pressure

In Dumas' method for the estimation of nitrogen, $$0.5\text{ g}$$ of an organic compound yielded $$60\text{ mL}$$ of nitrogen gas collected at $$300\text{ K}$$ temperature and $$715\text{ mm Hg}$$ pressure. Calculate the percentage composition of nitrogen in the compound.
(Given: Aqueous tension at $$300\text{ K} = 15\text{ mm Hg}$$).

Which one of the following set of elements can be detected using sodium fusion extract?

A flask contains a mixture of isohexane and 3-methylpentane. One of the liquids boils at 63$$^\circ$$C while the other boils at 60$$^\circ$$C. What is the best way to separate the two liquids and which one will be distilled out first?

In Dumas' method for estimation of nitrogen, 0.5 gram of an organic compound gave 60 mL of nitrogen collected at 300 K temperature and 715 mm Hg pressure. The percentage composition of nitrogen in the compound (Aqueous tension at 300 K = 15 mm Hg) is