Practical and Analytical Chemistry — JEE Main PYQs

To an aqueous solution containing ions such as ${\mathrm{Al}}^{3+},{\mathrm{Zn}}^{2+},{\mathrm{Ca}}^{2+},{\mathrm{Fe}}^{3+},{\mathrm{Ni}}^{2+},{\mathrm{Ba}}^{2+}$ and ${\mathrm{Cu}}^{2+}$ was added conc. HCl , followed by ${\mathrm{H}}_2\mathrm{S}$.
The total number of cations precipita …

In chromatography technique, the purification of compound is independent of:

Match List - I with List - II

List - I: Test / Reagents / Observation(s)
List - II: Species detected

The correct match is:

In Duma's method of estimation of nitrogen, 0.1840 g of an organic compound gave 30 mL of nitrogen collected at 287 K and 758 mm of Hg pressure. The percentage composition of nitrogen in the compound is _____. (Round off to the nearest integer).
[Given: Aqueous tension at …

10.0 mL of ${\mathrm{Na}}_2{\mathrm{CO}}_3$ solution is titrated against 0.2 M HCl solution.
The following titre values were obtained in 5 readings:
$4.8\mathrm{mL},4.9\mathrm{mL}5.0\mathrm{mL}5.0\mathrm{mL}$ and 5.0 mL
Based on these readings, and convention of titri …

Nitrogen can be estimated by Kjeldahl's method for which of the following compound?

Reagent, 1-naphthylamine and sulphanilic acid in acetic acid is used for the detection of :

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 1 M H₂SO₄ would have been neutralized by the ammonia evolved during the analysis.

A Chromatography column, packed with silica gel as stationary phase, was used to separate a mixture of compounds consisting of (a) benzanilide, (b) aniline and (c) acetophenone. When the column is eluted with a mixture of solvents, hexane; ethyl acetate(20:80), the sequence of ob …

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

The strength of an aqueous NaOH solution is most accurately determined by titrating : (Note : consider that an appropriate indicator is used)

Kjeldahl's method cannot be used to estimate nitrogen for which of the following compounds?

A chemist has 4 samples of artificial sweetener A, B, C and D. To identify these samples, he performed certain experiments and noted the following observations:
(i) A and D both form blue-violet colour with ninhydrin.
(ii) Lassaigne extract of C gives positive ${\mathrm{AgNO}}_3$ …

The Kjeldahl method of Nitrogen estimation fails for which of the following reaction products?
(a)
(see structure)
(b)
(see structure)
(c)
(see structure)
(d)
(see structure)

Match the following:

Test / Method
(i) Lucas Test
(ii) Dumas method
(iii) Kjeldahl's method
(iv) Hinsberg Test

Reagent
(a) ${\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{SO}}_2\mathrm{Cl}/$ aq. KOH
(b) ${\mathrm{HNO}}_3/{\mathrm{AgNO}}_3$
(c) $\mathrm{CuO}/{\mathrm{CO}}_2$ …

In an estimation of bromine by Carius method, 1.6 g of an organic compound gave 1.88 g of AgBr . The mass percentage of bromine in the compound is ____
(Atomic mass, $\mathrm{Ag}=108,\mathrm{Br}=80\mathrm{g}{\mathrm{mol}}^{-1}$ )

If dichloromethane(DCM) and water( ${\mathrm{H}}_2\mathrm{O}$ ) are used for differential extraction, which one of the following statements is correct?

25 mL of the given HCl solution requires 30 mL of 0.1 M sodium carbonate solution. What is the volume of this HCl solution required to titrate 30 mL of 0.2 M aqueous NaOH solution?

An organic compound 'A' is oxidized with ${\mathrm{Na}}_2{\mathrm{O}}_2$ followed by boiling with ${\mathrm{HNO}}_3$. The resultant solution is then treated with ammonium molybdate to yield a yellow precipitate. Based on above observation, the element present in the given compou …

In chromatography, which of the following statements is INCORRECT for ${\mathrm{R}}_f$ ?

The correct match between items I and II is:

Item - I (Mixture)
(a) $\mathrm{H}{}_2\mathrm{O}$ : Sugar
(b) $\mathrm{H}{}_2\mathrm{O}$ : Aniline
(c) $\mathrm{H}{}_2\mathrm{O}$ : Toluene

Item - II (Separation method)
p. Sublimation
q. Recrystallization
r. Stem distillation
s. Differential extraction

An organic compound is estimated through Dumus method and was found to evolve 6 mole of ${\mathrm{CO}}_2$ 4 moles of ${\mathrm{H}}_2\mathrm{O}$ and 1 mole of nitrogen gas. The formula of the compound is:

The correct match between item I and item II is
Item I
Item II
(a) Benzaldehyde
(b) Alumina
(c) Acetonitrile
(p) Mobile phase
(q) Adsorbent
(r) Adsorbate

The principle of column chromatography is

Which of the following compounds will be suitable for Kjeldahl's method for nitrogen estimation ?

Sodium salt of an organic acid 'X' reacts with aqueous CaCl₂ solution to give a white precipitate. The organic acid salt 'X' is:

The distillation technique most suited for separating glycerol from spent-lye in the soap industry is :

In Carius method of estimation of halogens, 250 mg of an organic compound gave 141 mg of AgBr . The percentage of bromine in the compound is: (at. Mass $\mathrm{Ag}=108;\mathrm{Br}=80)$

For the estimation of nitrogen, 1.4 g of organic compound was digested by Kjeldahl method and the evolved ammonia was absorbed in 60 mL of $\frac{\mathrm{M}}{10}$ sulphuric acid. The unreacted acid required 20 ml of $\frac{\mathrm{M}}{10}$ sodium hydroxide for complete neutraliza …

29.5 mg of an organic compound containing nitrogen was digested according to Kjeldahl's method and the evolved ammonia was absorbed in 20 mL of 0.1 M HCl solution. The excess of the acid required 15 mL of 0.1 M NaOH solution for complete neutralization. The percentage of nitrogen …

Amount of oxalic acid present in a solution can be determined by its titration with ${\mathrm{KMnO}}_4$ solution in the presence of ${\mathrm{H}}_2{\mathrm{SO}}_4$. The titration gives unsatisfactory result when carried out in the presence of HCl, because HCl

Calomel $\left({\mathrm{Hg}}_2{\mathrm{Cl}}_2\right)$ on reaction with ammonium hydroxide gives

The compound formed in the positive test for nitrogen with the Lassaigne solution of an organic compound is

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