JEE Main Chemistry — Organic Chemistry previous year questions with solutions.
For the given compounds, the correct order of increasing \(\mathrm{pK}_{\mathrm{a}}\) value :  Choose the correct answer from the options given below :
The adsorbent used in adsorption chromatography is/are - A. silica gel B. alumina C. quick lime D. magnesia Choose the most appropriate answer from the options given below :
 Acid $D$ formed in above reaction is:
Number of geometrical isomers possible for the given structure is/are _________. 
Given below are two statements: Statement - I: High concentration of strong nucleophilic reagent with secondary alkyl halides which do not have bulky substituents will follow ${S}_{N}2$ mechanism. Statement - II: A secondary alkyl halide when treated with a large excess of ethanol follows ${S}_{N}1$ mechanism. In the the light of the above statements, choose the most appropriate from the questions given below:
Match List - I with List - II. <table class="pyq-table"><tbody><tr><td colspan="2" rowspan="1">List-I (Reactants)</td><td colspan="2" rowspan="1">List-II Products</td></tr><tr><td>(A)</td><td>Phenol, $\mathrm{Zn}/\Delta$</td><td>(I)</td><td>Salicylaldehyde</td></tr><tr><td>(B)</td><td>Phenol, ${\mathrm{CHCl}}_{3},\mathrm{NaOH},\mathrm{HCl}$</td><td>(II)</td><td>Salicylic acid</td></tr><tr><td>(C)</td><td>Phenol, ${\mathrm{CO}}_{2},\mathrm{NaOH},\mathrm{HCl}$</td><td>(III)</td><td>Benzene</td></tr><tr><td>(D)</td><td>Phenol, $\text{ Conc. }{\mathrm{HNO}}_{3}$</td><td>(IV)</td><td>Picric acid</td></tr></tbody></table>Choose the correct answer from the options given below.
Relative stability of the contributing structures is : 
Match List I with List II \(\begin{array}{|l|l|c|l|} \hline & \text{List - I} & & \text{List - II} \\ \hline \text { A. } & \alpha \text { - Glucose and } \alpha \text { - Galactose } & \text { I. } & \text { Functional isomers } \\ \hline \text { B. } & \alpha \text { - Glucose and } \beta \text { - Glucose } & \text { II. } & \text { Homologous } \\ \hline \text { C. } & \alpha \text { - Glucose and } \alpha \text { - Fructose } & \text { III. } & \text { Anomers } \\ \hline \text { D. } & \alpha \text { - Glucose and } \alpha \text { - Ribose } & \text { IV. } & \text { Epimers } \\ \hline \end{array}\) Choose the correct answer from the options given below:
DNA molecule contains 4 bases whose structure are shown below. One of the structures is not correct, identify the incorrect base structure.
Which among the following has highest boiling point?
Number of carbocations from the following that are not stabilized by hyperconjugation is _______ 
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): \(\mathrm{S}_{\mathrm{N}} 2\) reaction of \(\mathrm{C}_6 \mathrm{H}_5 \mathrm{CH}_2 \mathrm{Br}\) occurs more readily than the \(\mathrm{S}_{\mathrm{N}} 2\) reaction of \(\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{Br}\). Reason (R) : The partially bonded unhybridized p-orbital that develops in the trigonal bipyramidal transition state is stabilized by conjugation with the phenyl ring. 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: Alcohols react both as nucleophiles and electrophiles. Reason R: Alcohols react with active metals such as sodium, potassium and aluminum to yield corresponding alkoxides and liberate hydrogen. In the light of the above statements, choose the correct answer from the options given below:
‘Adsorption’ principle is used for which of the following purification method?
Identify $A$ and $B$ in the following reaction sequence. 
Among the following, total number of meta directing functional groups is (Integer based) $-{\mathrm{OCH}}_{3},-{\mathrm{NO}}_{2},-\mathrm{CN},-{\mathrm{CH}}_{3}-{\mathrm{NHCOCH}}_{3}$, $-\mathrm{COR},-\mathrm{OH},-\mathrm{COOH},-\mathrm{Cl}$
In qualitative test for identification of presence of phosphorous, the compound is heated with an oxidising agent. Which is further treated with nitric acid and ammonium molybdate respectively. The yellow coloured precipitate obtained is :
Which of the following has highly acidic hydrogen?
Which among the following purification methods is based on the principle of “Solubility” in two different solvents?
Identify the major products \(\mathrm{A}\) and \(\mathrm{B}\) respectively in the following set of reactions. 
Which among the following aldehydes is most reactive towards nucleophilic addition reactions?
The arenium ion which is not involved in the bromination of Aniline is
The products A and B formed in the following reaction scheme are respectively 
In the Claisen-Schmidt reaction to prepare \(351 \mathrm{~g}\) of dibenzalacetone using \(87 \mathrm{~g}\) of acetone, the amount of benzaldehyde required is ______ g. (Nearest integer)