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Principles Related to Practical Chemistry · Question 9

JEE Main 2026 (Online) 4th April Morning ShiftMCQEasy📈 Topic in 16% papers+4−1
1

Identify the colour of compound 'X' in the sequence of the reaction. [figure]

  1. Violet
  2. Green
  3. Red
  4. Colourless

Answer

(4) Colourless

Solution

Phenol and phthalic anhydride condense (conc. H2SO4) to phenolphthalein, a colourless lactone (central sp3 carbon).

With NaOH the lactone ring opens and both –OH groups ionise; the central carbon becomes sp2 and the dianion has a quinonoid structure with extended conjugation over the whole molecule ⇒ it absorbs visible light ⇒ pink.

In excess (strongly alkaline) NaOH, OH- adds to the central sp2 carbon giving the carbinol trianion X.

In X the central carbon is again sp3; the conjugation between the rings is broken and no quinonoid chromophore is left.

∴ X does not absorb in the visible region – it is colourless (this is why the pink colour fades in very strong alkali).

Answer: (4)

JEE Main 2026 (Online) 4th April Morning Shift

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2

2.0 g of a bromo hydrocarbon (X) was subjected to Carius analysis, gave 3.36 g of AgBr. The percentage of carbon in the compound (X) is 26.7%. Total number of carbon atoms in the empirical formula for compound (X) is . (Given molar mass in g mol-1 H : 1, C : 12, Br : 80, Ag : 108)

JEE Main 2026 (Online) 4th April Morning Shift
3

Among Fe3+, Pb2+, Cu2+ and Mn2+, identify the one that gets precipitated out while passing H2S in presence of NH4OH as group reagent. The highest possible oxidation state of the corresponding metal is

  1. +3
  2. +4
  3. +2
  4. +7
JEE Main 2026 (Online) 4th April Evening Shift
4

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

  1. A-III, B-I, C-IV, D-II
  2. A-III, B-IV, C-I, D-II
  3. A-I, B-III, C-II, D-IV
  4. A-I, B-II, C-III, D-IV
JEE Main 2026 (Online) 4th April Evening Shift
5

In sulphur estimation, 2.0 10-3 mol of an organic compound (X) (molar mass 76 g mol-1) gave 0.4813 g of barium sulphate (molar mass 233 g mol-1). The percentage of sulphur in the compound (X) is 10-1 % (Nearest integer)

JEE Main 2026 (Online) 4th April Evening Shift
6

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below :

  1. Both Statement I and Statement II are true
  2. Both Statement I and Statement II are false
  3. Statement I is true but Statement II is false
  4. Statement I is false but Statement II is true
JEE Main 2026 (Online) 2nd April Morning Shift
7

Match List - I with List - II.

  1. A-IV, B-II, C-I, D-III
  2. A-IV, B-II, C-III, D-I
  3. A-II, B-IV, C-I, D-III
  4. A-II, B-IV, C-III, D-I
JEE Main 2026 (Online) 2nd April Morning Shift
8

A salt with few drops of conc. HCl gives apple green colour in flame test. The group precipitate of the salt is dissolved in acetic acid and treated with K2CrO4 to give yellow precipitate. When the sodium carbonate extract of the salt solution is heated with conc. HNO3 and ammonium molybdate, it resulted a canary yellow precipitate. The cation and anion present in the salt are respectively,

  1. Ca2+ and SO42-
  2. Ba2+ and PO43-
  3. Mn2+ and PO43-
  4. Ba2+ and SO42-
JEE Main 2026 (Online) 2nd April Morning Shift
9

Complete combustion of X g of an organic compound gave 0.25 g of CO2 and 0.12 g of H2O. If the % of carbon is 25% and of hydrogen is 4.89%, then X = 10-3 g. (Nearest integer) (Molar mass of C, H and O are 12, 1 and 16 g mol-1 respectively.)

  1. 273
  2. 27
  3. 2730
  4. 227
JEE Main 2026 (Online) 2nd April Evening Shift
10

Method used for separation of mixture of products (B and C) obtained in the following reaction is [figure]

  1. simple distillation
  2. sublimation
  3. fractional distillation
  4. steam distillation
JEE Main 2026 (Online) 28th January Morning Shift
11

Given below are two statements: In the light of the above statements, choose the correct answer from the options given below

  1. Statement I is true but Statement II is false
  2. Both Statement I and Statement II are false
  3. Statement I is false but Statement II is true
  4. Both Statement I and Statement II are true
JEE Main 2026 (Online) 28th January Morning Shift

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