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Principles Related to Practical Chemistry · Question 38

JEE Main 2025 (Online) 7th April Morning ShiftMCQEasy📈 Topic in 29% papers+4−1
1

When a salt is treated with sodium hydroxide solution it gives gas X. On passing gas X through reagent Y a brown coloured precipitate is formed. X and Y respectively, are

  1. X = NH3 and Y = HgO
  2. X = NH4Cl and Y = KOH
  3. X = NH3 and Y = K2HgI4 + KOH
  4. X = HCl and Y = NH4Cl

Answer

(3) X = NH3 and Y = K2HgI4 + KOH

Solution

An ammonium salt with NaOH liberates ammonia:

NH4Cl + NaOH NaCl + NH3 + H2O X = NH3

NH3 passed through Nessler's reagent (alkaline K2HgI4) gives a brown precipitate (iodide of Millon's base):

2K2HgI4 + NH3 + 3KOH HgO Hg(NH2)I + 7KI + 2H2O

Y = K2HgI4 + KOH

Answer: (3)

JEE Main 2025 (Online) 7th April Morning Shift

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2

An organic compound weighing 500 mg, produced 220 mg of CO2, on complete combustion. The percentage composition of carbon in the compound is %. (nearest integer) (Given molar mass in g mol-1 of C : 12, O : 16)

JEE Main 2025 (Online) 7th April Morning Shift
3

A mixture of 1 g each of chlorobenzene, aniline, and benzoic acid is dissolved in 50 mL ethyl acetate and placed in a separating funnel. 5 M NaOH (30 mL) was added in the same funnel. The funnel was shaken vigorously and then kept aside. The ethyl acetate layer in the funnel contains :

  1. chlorobenzene and aniline
  2. benzoic acid and aniline
  3. benzoic acid
  4. benzoic acid and chlorobenzene
JEE Main 2025 (Online) 7th April Evening Shift
4

In Dumas' method 292 mg of an organic compound released 50 mL of nitrogen gas (N2) at 300 K temperature and 715 mm Hg pressure. The percentage composition of 'N' in the organic compound is % (Nearest integer) (Aqueous tension at 300 K = 15 mm Hg)

JEE Main 2025 (Online) 7th April Evening Shift
5

In Dumas' method for estimation of nitrogen 1 g of an organic compound gave 150 mL of nitrogen collected at 300 K temperature and 900 mm Hg pressure. The percentage composition of nitrogen in the compound is % (nearest integer) (Aqueous tension at 300 K = 15 mm Hg)

JEE Main 2025 (Online) 4th April Morning Shift
6

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

  1. (A)-(IV), (B)-(III), (C)-(II), (D)-(I)
  2. (A)-(I), (B)-(II), (C)-(III), (D)-(IV)
  3. (A)-(III), (B)-(IV), (C)-(I), (D)-(II)
  4. (A)-(II), (B)-(I), (C)-(IV), (D)-(III)
JEE Main 2025 (Online) 4th April Evening Shift
7

During estimation of nitrogen by Dumas' method of compound X (0.42 g) [figure] mL of N2 gas will be liberated at STP. (nearest integer) (Given molar mass in g mol-1 : C : 12, H : 1, N : 14)

JEE Main 2025 (Online) 3rd April Morning Shift
8

0.5 g of an organic compound on combustion gave 1.46 g of CO2 and 0.9 g of H2O. The percentage of carbon in the compound is . (Nearest integer) [Given : Molar mass (in g mol-1) C : 12, H : 1, O : 16]

JEE Main 2025 (Online) 3rd April Morning Shift
9

Compounds that should not be used as primary standards in titrimetric analysis are : Choose the most appropriate answer from the options given below:

  1. C, D and E Only
  2. B and D Only
  3. D and E Only
  4. A, C and D Only
JEE Main 2025 (Online) 3rd April Evening Shift
10

In Dumas' method for estimation of nitrogen 0.4 g 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 is (Given : Aqueous tension at 300 K = 15 mm Hg)

  1. 15.71\%
  2. 17.46\%
  3. 7.85\%
  4. 20.95\%
JEE Main 2025 (Online) 3rd April Evening Shift
11

Choose the correct tests with respective observations. Choose the correct answer from the options given below :

  1. A, D and E only
  2. A, B and C only
  3. B, D and E only
  4. C, D and E only
JEE Main 2025 (Online) 2nd April Morning Shift

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