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Optical activity of an enantiomeric mixture is \( +12.6^\circ \) and the specific rotation of \( (+) \) isomer is \( +30^\circ \). The optical purity is _______ \( \% \).

In the following structures, which one is having staggered conformation with maximum dihedral angle?

Given below are two statements.
Statement I: The presence of weaker \( \pi \)- bonds make alkenes less stable then alkanes.
Statement II: The strength of the double bond is greater than that of carbon-carbon single bond.
In the light of the above statements, choose the correct answer from the options given below.

In base vs. acid titration, at the end point methyl orange is present as:

The correct IUPAC name of the following compound is:

The formula of the purple colour formed in Lassaigne's test for sulphur using sodium nitroprusside is:

The complete combustion of \( 0.492 \, \text{g} \) of an organic compound containing \( \text{‘C’, ‘H’ and ‘O’} \) gives \( 0.793 \, \text{g} \) of \( \mathrm{CO_2} \) and \( 0.442 \, \text{g} \) of \( \mathrm{H_2O} \). The percentage of oxygen composition in the organic compound is ______ (nearest integer)

Phenol on reaction with dilute nitric acid, gives two products. Which method will be most efficient for large scale separation?

120 g of an organic compound that contains only carbon and hydrogen gives 330 g of $\text{CO}_2$ and 270 g of water on complete combustion. The percentage of carbon and hydrogen, respectively are:

Given below are two statement:

In the light of the above statement, choose the most appropriate answer from the options given below.

Given below are two statements: one is labelled as Assertion A and, the other is labelled as Reason R.
Assertion A: \( [6] \) Annulene, \( [8] \) Annulene and cis-\( [10] \) Annulene, are respectively aromatic, not-aromatic and aromatic.

Reason R: Planarity is one of the requirements of aromatic systems.
In the light of the above statements, choose the most appropriate answer from the options given below:

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R.
Assertion A : Thin layer chromatography is an adsorption chromatography.
Reason R : A thin layer of silica gel is spread over a glass plate of suitable size in thin layer chromatography which acts as an adsorbent.
In the light of the above statements, choose the correct answer from the options given below:

Observe structures of the following compounds

The total number of structures/compounds which possess asymmetric carbon atoms is __________.

Kjeldahl’s method was used for the estimation of nitrogen in an organic compound. The ammonia evolved from \( 0.55 \, \mathrm{g} \) of the compound neutralized \( 12.5 \, \mathrm{mL} \) of \( 1 \, \mathrm{M} \, \mathrm{H_2SO_4} \) solution. The percentage of nitrogen in the compound is __________. (Nearest integer)

The IUPAC name of ethylidene chloride is:

A sample of \( 0.125 \, \text{g} \) of an organic compound when analyzed by Duma’s method yields \( 22.78 \, \text{mL} \) of nitrogen gas collected over KOH solution at \( 280 \, \text{K} \) and \( 759 \, \text{mm Hg} \). The percentage of nitrogen in the given organic compound is ________ . (Nearest integer)
Given: (a) The vapour pressure of water of \( 280 \, \text{K} \) is \( 14.2 \, \text{mm Hg} \).
(b) \( R = 0.082 \, \text{L atm K}^{-1} \text{ mol}^{-1} \)

Which of the following is most stable?

Which technique among the following, is most appropriate in separation of a mixture of \( 100 \, \text{mg} \) of p-nitrophenol and picric acid?

While estimating the nitrogen present in an organic compound by Kjeldahl’s method, the ammonia evolved from \( 0.25 \, \text{g} \) of the compound neutralized \( 2.5 \, \text{mL} \) of \( 2 \, \text{M} \, \mathrm{H_2SO_4} \). The percentage of nitrogen present in organic compound is ______.

On complete combustion \( 0.30 \, \text{g} \) of an organic compound gave \( 0.20 \, \text{g} \) of carbon dioxide and \( 0.10 \, \text{g} \) of water. The percentage of carbon in the given organic compound is ____________ (Nearest integer)

Arrange the following carbocations in decreasing order of stability.

In Carius method of estimation of halogen, \(0.45\,\text{g}\) of an organic compound gave \(0.36\,\text{g}\) of \(\mathrm{AgBr}\). Find out the percentage of bromine in the compound.
[Molar masses: \(\mathrm{AgBr}=188\,\mathrm{g\,mol^{-1}}\); \(\mathrm{Br}=80\,\mathrm{g\,mol^{-1}}\)]

\( 0.25 \, \text{g} \) of an organic compound containing chlorine gave \( 0.40 \, \text{g} \) of silver chloride in Carius estimation. The percentage of chlorine present in the compound is ______. [in nearest integer]
(Given: Molar mass of \( \text{Ag} \) is \( 108 \, \text{g mol}^{-1} \) and that of \( \text{Cl} \) is \( 35.5 \, \text{g mol}^{-1} \) )

\( 0.2 \, \text{g} \) of an organic compound was subjected to estimation of nitrogen by Dumas method in which volume of \( \text{N}_2 \) evolved (at STP) was found to be \( 22.400 \, \text{mL} \). The percentage of nitrogen in the compound is __________. [nearest integer]
(Given: Molar mass of \( \text{N}_2 \) is \( 28 \, \text{g mol}^{-1} \), Molar volume of \( \text{N}_2 \) at STP : \( 22.4 \, \text{L} \))

Which of the following carbocations is most stable?

The separation of two coloured substances was done by paper chromatography. The distances travelled by solvent front, substance A and substance B from the base line are \( 3.25 \, \text{cm} \), \( 2.08 \, \text{cm} \) and \( 1.05 \, \text{cm} \), respectively. The ratio of \( R_f \) values of A to B is ________.

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JEE Main 2022 25th July Evening Shift

In base vs. acid titration, at the end point methyl orange is present as: