datavorous/entrance-exam-dataset huggingface dataset:
Which of the following reactions can produce aniline as main product?

Options:
A $\mathrm{C}_6 \mathrm{H}_5 \mathrm{NO}_2+\mathrm{Zn} / \mathrm{KOH}$
B $\mathrm{C}_6 \mathrm{H}_5 \mathrm{NO}_2+\mathrm{Zn} / \mathrm{NH}_4 \mathrm{Cl}$
C $\mathrm{C}_6 \mathrm{H}_5 \mathrm{NO}_2+\mathrm{LiAlH}_4$
D $\mathrm{C}_6 \mathrm{H}_5 \mathrm{NO}_2+\mathrm{Zn} / \mathrm{HCl}$

The correct answer is:
$\mathrm{C}_6 \mathrm{H}_5 \mathrm{NO}_2+\mathrm{Zn} / \mathrm{HCl}$

Solution:
Reduction of nitrobenzene in acidic medium forms aniline as-

Topic: Chemistry, Amines, TS EAMCET, TS EAMCET 2006
Which of the following reactions can produce aniline as main product?

Options:
A $\mathrm{C}_6 \mathrm{H}_5 \mathrm{NO}_2+\mathrm{Zn} / \mathrm{KOH}$
B $\mathrm{C}_6 \mathrm{H}_5 \mathrm{NO}_2+\mathrm{Zn} / \mathrm{NH}_4 \mathrm{Cl}$
C $\mathrm{C}_6 \mathrm{H}_5 \mathrm{NO}_2+\mathrm{LiAlH}_4$
D $\mathrm{C}_6 \mathrm{H}_5 \mathrm{NO}_2+\mathrm{Zn} / \mathrm{HCl}$

The correct answer is:
$\mathrm{C}_6 \mathrm{H}_5 \mathrm{NO}_2+\mathrm{Zn} / \mathrm{HCl}$

Solution:
Reduction of nitrobenzene in acidic medium forms aniline as-

Topic: Chemistry, Amines, AP EAMCET, AP EAMCET 2006
Which of the following reactions can produce aniline as main product?

Options:
A $\mathrm{C}_6 \mathrm{H}_5 \mathrm{NO}_2+\mathrm{Zn} / \mathrm{KOH}$
B $\mathrm{C}_6 \mathrm{H}_5 \mathrm{NO}_2+\mathrm{Zn} / \mathrm{NH}_4 \mathrm{Cl}$
C $\mathrm{C}_6 \mathrm{H}_5 \mathrm{NO}_2+\mathrm{LiAlH}_4$
D $\mathrm{C}_6 \mathrm{H}_5 \mathrm{NO}_2+\mathrm{Zn} / \mathrm{HCl}$

The correct answer is:
$\mathrm{C}_6 \mathrm{H}_5 \mathrm{NO}_2+\mathrm{Zn} / \mathrm{HCl}$

Solution:
Reduction of nitrobenzene in acidic medium forms aniline as-

Topic: Chemistry, Amines, JEE Main
Which of the following reactions can produce aniline as main product?

Options:
A $\mathrm{C}_6 \mathrm{H}_5 \mathrm{NO}_2+\mathrm{Zn} / \mathrm{KOH}$
B $\mathrm{C}_6 \mathrm{H}_5 \mathrm{NO}_2+\mathrm{Zn} / \mathrm{NH}_4 \mathrm{Cl}$
C $\mathrm{C}_6 \mathrm{H}_5 \mathrm{NO}_2+\mathrm{LiAlH}_4$
D $\mathrm{C}_6 \mathrm{H}_5 \mathrm{NO}_2+\mathrm{Zn} / \mathrm{HCl}$

The correct answer is:
$\mathrm{C}_6 \mathrm{H}_5 \mathrm{NO}_2+\mathrm{Zn} / \mathrm{HCl}$

Solution:
Various products are formed when nitroarenes are reduced. These are given below for $\mathrm{C}_6 \mathrm{H}_5 \mathrm{NO}_2$.
$$
\text { Medium } \quad \text { Main product }
$$
(d) In acidic medium Aniline $\left(\mathrm{C}_6 \mathrm{H}_5 \mathrm{NH}_2\right)$ $(\mathrm{metal} / \mathrm{HCl})$
(b) In neutral medium Phenyl hydroxylamine, $\left(\mathrm{Zn} / \mathrm{NH}_4 \mathrm{Cl}\right)$
$$
\text { (a) In alkaline medium }
$$
Thus, aniline will be main product in case of (d).

Topic: Chemistry, Amines, VITEEE, VITEEE 2021
Which of the following reactions converts an aldehyde to a primary alcohol?

Options:
A Oxidation with $\mathrm{KMnO}_4$
B Reduction with $\mathrm{NaBH}_4$
C Reaction with $\mathrm{Br}_2$ in $\mathrm{CCl}_4$
D Reaction with $\mathrm{SOCl}_2$

The correct answer is:
Reduction with $\mathrm{NaBH}_4$

Solution:
Reduction with $\mathrm{NaBH}_4$
Explanation: Sodium borohydride $\left(\mathrm{NaBH}_4\right)$ reduces aldehydes to primary alcohols.

Topic: Chemistry, Alcohols Phenols and Ethers, JEE Main
Which of the following reactions does not occur?

Options:
A
B
C
D

The correct answer is:

Solution:
As this compound do not have any hydrogen atom on alkyl group linked with benzene ring so this reaction is not possible.
All other reactions are possible.

Topic: Chemistry, Carboxylic Acid Derivatives, JEE Main
Which of the following reactions does not take place?

Options:
A F2+2Cl-â2F-+Cl2
B Br 2 +2 I − →2 Br − + I 2
C Cl2+2Br-â2Cl-+Br2
D Cl2+2F-â2Cl-+F2

The correct answer is:
Cl2+2F-→2Cl-+F2

Solution:
Cl2 cannot displace F2 but F2 can displace Cl2 on account of its higher electronegativity.
The SRP value of F2 is highest in the electrochemtextcal series. So it will oxidise chlorine.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main
Which of the following reactions give(s) a meso-compound as the main product?

Options:
A
B
C
D

The correct answers are:
,

Solution:
Hint:

Topic: Chemistry, Hydrocarbons, WBJEE, WBJEE 2020
Which of the following reactions gives carboxylate ion in their reaction mixture?

Options:
A I and II
B II and III
C I and III
D III and IV

The correct answer is:
II and III

Solution:
So, in reactions (II) and (III), carboxylate ion is present in their reaction mixture.

Topic: Chemistry, Carboxylic Acid Derivatives, JEE Main
Which of the following reactions involves $\alpha$ -halogenation of carboxylic acid?

Options:
A Gattermann reaction
B Riemer - Tiemann reaction
C Sandmeyer reaction
D Hell-Vohlard-Zelinsky reaction

The correct answer is:
Hell-Vohlard-Zelinsky reaction

Solution:
Hell Volhard Zelinsky (HVZ) reaction:
This reaction involves alpha bromination of carboxylic acids. Carboxylic acids react with chlorine or bromine in presence of small amount of red phosphorous to give alpha halo carboxylic acids.
$\mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{COOH} \stackrel{\mathrm{Br}_{2} / \mathrm{P}}{\rightarrow} \mathrm{CH}_{3}-\mathrm{CHBr}-\mathrm{COOH} \stackrel{\mathrm{Br}_{2} / \mathrm{P}}{\rightarrow} \mathrm{CH}_{3}-\mathrm{CBr}_{2}-$
$\mathrm{COOH} \stackrel{\mathrm{Br}_{2} / \mathrm{P}}{\longrightarrow}$ No further reaction.

Topic: Chemistry, Carboxylic Acid Derivatives, JEE Main
Which of the following reactions involves oxidation-reduction

Options:
A $\mathrm{NaBr}+\mathrm{HCl} \rightarrow \mathrm{NaCl}+\mathrm{HBr}$
B $\mathrm{HBr}+\mathrm{AgNO}_3 \rightarrow \mathrm{AgBr}+\mathrm{HNO}_3$
C $\mathrm{H}_2+\mathrm{Br}_2 \rightarrow 2 \mathrm{HBr}$
D $2 \mathrm{NaOH}+\mathrm{H}_2 \mathrm{SO}_4 \rightarrow \mathrm{Na}_2 \mathrm{SO}_4+2 \mathrm{H}_2 \mathrm{O}$

The correct answer is:
$\mathrm{H}_2+\mathrm{Br}_2 \rightarrow 2 \mathrm{HBr}$

Solution:

Topic: Chemistry, Redox Reactions, JEE Main
Which of the following reactions is an example of a redox reaction?

Options:
A XeF2+PF5→XeF+PF6-
B XeF6+H2O→XeOF4+2HF
C XeF6+2H2O→XeO2F2+4HF
D XeF4+O2F2→XeF6+O2

The correct answer is:
XeF4+O2F2→XeF6+O2

Solution:
Redox reaction: ↓ Se=Decrease, ↑Se=Increase
XeF4 is oxidized while O2F2 is reduced.

Topic: Chemistry, p Block Elements (Group 15, 16, 17 & 18), JEE Main, JEE Main 2017 (02 Apr)
Which of the following reactions is an example of nucleophilic substitution reaction?

Options:
A $\mathrm{RX}+\mathrm{Mg} \rightarrow \mathrm{RMgX}$
B $\mathrm{RX}+\mathrm{KOH} \rightarrow \mathrm{ROH}+\mathrm{KX}$
C $2 \mathrm{RX}+2 \mathrm{Na} \rightarrow \mathrm{R}-\mathrm{R}+2 \mathrm{NaX}$
D $\mathrm{RX}+\mathrm{H}_2 \rightarrow \mathrm{RH}+\mathrm{HX}$

The correct answer is:
$\mathrm{RX}+\mathrm{KOH} \rightarrow \mathrm{ROH}+\mathrm{KX}$

Solution:
$\mathrm{R}-\mathrm{X}+\mathrm{KOH} \rightarrow \mathrm{R}-\mathrm{OH}+\mathrm{KX}$
$\mathrm{X}-$ replaced by $\mathrm{OH}-$ show nucleophilic substitution reaction

Topic: Chemistry, Chemistry in Everyday Life, NEET, NEET 2009 (Mains)
Which of the following reactions is not involved in serpeck's process of leaching of Al2O3 from white bauxite ore?

Options:
A Al2O3+N2+3C→Δ2AlN+3CO
B SiO2+C→ΔSi+2CO
C Na2CO3+Al2O3→Δ2NaAlO2+CO2
D 2AlOH3→ΔAl2O3+3H2O

The correct answer is:
Na2CO3+Al2O3→Δ2NaAlO2+CO2

Solution:
Na2CO3+Al2O3→Δ2NaAlO2+CO2 is involved in Hall's process.

Topic: Chemistry, p Block Elements (Group 13 & 14), JEE Main
Which of the following reactions is used to convert a carboxylic acid directly to an amide?

Options:
A Esterification followed by reduction
B Direct reaction with ammonia or an amine
C Oxidation with $\mathrm{KMnO}_4$
D Friedel-Crafts acylation

The correct answer is:
Direct reaction with ammonia or an amine

Solution:
Direct reaction with ammonia or an amine
Explanation: Carboxylic acids can be directly converted to amides by reacting with ammonia $\left(\mathrm{NH}_3\right)$ or an amine $\left(\mathrm{R}-\mathrm{NH}_2\right)$. This reaction typically involves heating the carboxylic acid with excess ammonia or amine to drive the reaction to completion. The carboxylic acid undergoes nucleophilic substitution by the ammonia or amine, resulting in the formation of the corresponding amide

Topic: Chemistry, Amines, JEE Main
Which of the following reactions is used to prepare aryl fluorides from diazonium salts and fluoroboric acid?

Options:
A Sandmeyer reaction
B Balz-Schiemann reaction
C Gattermann reaction
D Swarts reaction

The correct answer is:
Balz-Schiemann reaction

Solution:
Balz-Schiemann reaction.
The Schiemann reaction (also called the Balz–Schiemann reaction) is a chemical reaction in which a primary aromatic amine is transformed to an Aryl fluoride via a diazonium tetrafluoroborate intermediate.This reaction is a key method to form the fluorobenzene by the thermal decomposition of the diazonium tetraflouroborate proceeds without a promoter and is believed to generate highly unstable aryl cations (Ar+), which abstract F- from BF4- to give the fluoroarene (ArF), along with boron triflouride as the byproduct.

Topic: Chemistry, Amines, JEE Main
Which of the following reactions is used to prepare ketones from carboxylic acids?

Options:
A Aldol condensation
B Cannizzaro reaction
C Kolbe-Schmitt reaction
D Decarboxylation followed by hydration of alkyne

The correct answer is:
Decarboxylation followed by hydration of alkyne

Solution:
Decarboxylation followed by hydration of alkyne
Explanation: Carboxylic acids can be converted to ketones via decarboxylation to form alkanes, which can then be further converted to ketones by hydration of alkynes.

Topic: Chemistry, Alcohols Phenols and Ethers, JEE Main
Which of the following reactions leads to the formation of a substance in the colloidal state

Options:
A $\mathrm{Cu}+\mathrm{HgCl}_2 \rightarrow \mathrm{CuCl}_2+\mathrm{Hg}$
B $2 \mathrm{HNO}_3+3 \mathrm{H}_2 \mathrm{~S} \rightarrow 3 \mathrm{~S}+4 \mathrm{H}_2 \mathrm{O}+2 \mathrm{NO}$
C $2 \mathrm{Mg}+\mathrm{CO}_2 \rightarrow 2 \mathrm{MgO}+\mathrm{C}$
D $\mathrm{Cu}+\mathrm{CuCl}_2 \rightarrow \mathrm{Cu}_2 \mathrm{Cl}_2$

The correct answer is:
$2 \mathrm{HNO}_3+3 \mathrm{H}_2 \mathrm{~S} \rightarrow 3 \mathrm{~S}+4 \mathrm{H}_2 \mathrm{O}+2 \mathrm{NO}$

Solution:
Correct option is 2. $2 \mathrm{HNO} \mathrm{O}_3+3 \mathrm{H}_2 \mathrm{~S} \rightarrow 3 \mathrm{~S}+4 \mathrm{H}_2 \mathrm{O}+2 \mathrm{NO}$
$2 \mathrm{HNO}_3+3 \mathrm{H}_2 \mathrm{~S} \rightarrow \underset{\text { sol }}{3 \mathrm{~S}}+4 \mathrm{H}_2 \mathrm{O}+2 \mathrm{NO}_2$
Sulphur sol contains large aggregates of sulphur molecules such that the size of aggregate come in colloidal range.

Topic: Chemistry, Surface Chemistry, JEE Main
Which of the following reactions occurs at the cathode during the charging of a lead storage battery

Options:
A $\mathrm{Pb}^{2+}+2 e^{-} \rightarrow \mathrm{Pb}$
B $\mathrm{Pb}^{2+}+\mathrm{SO}_4^{2-} \rightarrow \mathrm{PbSO}_4$
C $\mathrm{Pb} \rightarrow \mathrm{Pb}^{2+}+2 e^{-}$
D $\mathrm{PbSO}_4+2 \mathrm{H}_2 \mathrm{O} \rightarrow 2 \mathrm{PbO}_2+4 \mathrm{SO}_4^{2-}+2 e^{-}$

The correct answer is:
$\mathrm{PbSO}_4+2 \mathrm{H}_2 \mathrm{O} \rightarrow 2 \mathrm{PbO}_2+4 \mathrm{SO}_4^{2-}+2 e^{-}$

Solution:
$\mathrm{PbSO}_4+2 \mathrm{H}_2 \mathrm{O} \rightarrow 2 \mathrm{PbO}_2+4 \mathrm{SO}_4^{2-}+2 e^{-}$

Topic: Chemistry, Electrochemistry, JEE Main
Which of the following reactions occurs at the cathode of a common dry cell

Options:
A $M n \rightarrow \mathrm{Mn}^{2+}+2 e$
B $2 \mathrm{MnO}_2+\mathrm{Zn}^{2+}+2 e^{-} \rightarrow \mathrm{ZnMn}_2 \mathrm{O}_4$
C $2 \mathrm{ZnO}_2+\mathrm{Mn}^{2+}+2 \mathrm{e}^{-} \rightarrow \mathrm{MnZn}_2 \mathrm{O}_4$
D $Z n \rightarrow Z n^{2+}+2 e^{-}$

The correct answer is:
$2 \mathrm{MnO}_2+\mathrm{Zn}^{2+}+2 e^{-} \rightarrow \mathrm{ZnMn}_2 \mathrm{O}_4$

Solution:
In common dry cell.
Anode: $Z n \rightarrow Z n^{++}+2 e^{-}$
Cathode:
$2 \mathrm{MnO}_2+\mathrm{Zn}^{++}+2 e^{-} \rightarrow \mathrm{ZnMn}_2 \mathrm{O}_4$

Topic: Chemistry, Electrochemistry, JEE Main
Which of the following reaction/s will not give p -aminoazobenzene?

Options:
A B only
B A only
C C only
D A and B

The correct answer is:
B only

Solution:
In basic or neutral medium N-N coupling favourable while in slightly acidic medium CN coupling favourable.

Topic: Chemistry, Hydrocarbons, JEE Main, JEE Main 2021 (25 Feb Shift 1)
Which of the following reactions will not give propane

Options:
A $\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CH}_2 \mathrm{Cl} \xrightarrow[\mathrm{H}_2 \mathrm{O}]{\mathrm{Mg} / \text { ether }}$
B $\mathrm{CH}_3 \mathrm{COCl} \xrightarrow[\mathrm{H}_2 \mathrm{O}]{\mathrm{CH}_3 \mathrm{MgX}}$
C $\mathrm{CH}_3 \mathrm{CH}=\mathrm{CH}_2 \xrightarrow[\mathrm{CH}_3 \mathrm{COOH}]{\mathrm{B}_2 \mathrm{H}_6}$
D

The correct answer is:
$\mathrm{CH}_3 \mathrm{COCl} \xrightarrow[\mathrm{H}_2 \mathrm{O}]{\mathrm{CH}_3 \mathrm{MgX}}$

Solution:
With calculated amount of Grignard reagent, acetyl chloride forms ketones.
$\mathrm{CH}_3 \mathrm{COCl}+\mathrm{XMgCH}_3 \rightarrow \mathrm{CH}_3 \mathrm{COCH}_3+\mathrm{Mg} \lt \begin{aligned} & \mathrm{Cl} \\ & X\end{aligned}$

Topic: Chemistry, Hydrocarbons, JEE Main
Which of the following reactions will not produce a racemic product ?

Options:
A
B
C CH3CH2CH=CH2→HBr
D

The correct answer is:

Solution:
A solution of two enantiomers that are present in an equal ratio is known as the racemic mixture. Here the reaction sequence is given below. It is clearly seen from the final product that it is not the racemic product because it does not have any chiral carbon.

Topic: Chemistry, Hydrocarbons, JEE Main, JEE Main 2020 (09 Jan Shift 2)
Which of the following reactions will not result in the formation of carbon-carbon bonds?

Options:
A Cannizzaro reaction
B Wurtz reaction
C Reimer-Tiemann reaction
D Friedel-Crafts acylation

The correct answer is:
Cannizzaro reaction

Solution:
$\mathrm{C}-\mathrm{C}$ bond is not formed in Cannizaro reaction while other reactions result in the formation of $\mathrm{C}-\mathrm{C}$ bond.
Cannizaro reaction

Wurtz reaction
$2 R-X+2 \mathrm{Na} \longrightarrow R-R+2 \mathrm{Na} \times$

Topic: Chemistry, Aldehydes and Ketones, JEE Main
Which of the following reactions will occur?
1.ArN2++CuBr→ArBr
2.
3. ArN2++H3PO2→H2OArH
4. ArN2++I⊖→Arl
Select the correct answer using the order given below

Options:
A 1, 2 and 4
B 1, 3 and 4
C 1, 2 and 3
D 2, 3 and 4

The correct answer is:
1, 3 and 4

Solution:
The reaction with phenol is carried out the alkaline medium only (i.e., with phenoxide ion). The alkaline medium in 2 is not given.

Here 1, 3 and 4 reactions are possible.
1.ArN+2+CuBr→ArBr+N2
3.ArN+2+H3PO2→H2OArH+H3PO3+N2
4.ArN+2+I-→ArI+N2

Topic: Chemistry, Amines, JEE Main
Which of the following reactions will yield $2, 2-$dibromopropane?

Options:
A
$\mathrm{CH}_3-\mathrm{C} \equiv \mathrm{CH}+2 \mathrm{HBr} \longrightarrow$

B
$\mathrm{CH}_3 \mathrm{CH} \equiv \mathrm{CHBr}+\mathrm{HBr} \longrightarrow$

C
$\mathrm{CH} \equiv \mathrm{CH}+2 \mathrm{HBr} \longrightarrow$

D
$\mathrm{CH}_3-\mathrm{CH}=\mathrm{CH}_2+\mathrm{HBr} \longrightarrow$

The correct answer is:
$\mathrm{CH}_3-\mathrm{C} \equiv \mathrm{CH}+2 \mathrm{HBr} \longrightarrow$

Solution:
Hence, (A) is correct.

Topic: Chemistry, Haloalkanes and Haloarenes, JEE Main, JEE Main 2007
Which of the following reactions will yield 2, 2-dibromopropane

Options:
A $\mathrm{HC} \equiv \mathrm{CH}+2 \mathrm{HBr} \rightarrow$
B $\mathrm{CH}_3 \mathrm{C} \equiv \mathrm{CH}+2 \mathrm{HBr} \rightarrow$
C $\mathrm{CH}_3 \mathrm{CH}=\mathrm{CH}_2+\mathrm{HBr} \rightarrow$
D $\mathrm{CH}_3 \mathrm{CH}=\mathrm{CHBr}+\mathrm{HBr} \rightarrow$

The correct answer is:
$\mathrm{CH}_3 \mathrm{C} \equiv \mathrm{CH}+2 \mathrm{HBr} \rightarrow$

Solution:

Topic: Chemistry, Hydrocarbons, JEE Main
Which of the following reactions will yield benzaldehyde as a product?

Options:
A B & C
B C & D
C A & D
D A & C

The correct answer is:
A & D

Solution:

Topic: Chemistry, Alcohols Phenols and Ethers, JEE Main, JEE Main 2022 (27 Jun Shift 1)
Which of the following reactions would generate an electrophile?
(I)  (CH 3 ) 3 CBr + Anhy.  AlCl 3
(II) CH3–CH=CH2+H⊕
(III) C6H5COOH + H3O⊕
(IV) HNO3+H2SO4

Options:
A I, II and IV
B I, II and III
C I, II, III, IV
D II, III and IV

The correct answer is:
I, II and IV

Solution:
Here electrophile generation is possible in reactions I, II and IV as follows
(I)
(II) CH3–CH=CH2+H⊕→CH3–C⊕H–CH3
(III) C6H5COOH+H3O⊕→no reaction
IV HNO3 + H2SO4→NO2⊕ + H3O⊕ + HSO4−

Topic: Chemistry, General Organic Chemistry, JEE Main
Which of the following reacts with water with high rate

Options:
A $\mathrm{Li}$
B K
C $\mathrm{Na}$
D $R b$

The correct answer is:
$R b$

Solution:
$\begin{gathered}2 R b+2 \mathrm{H}_2 \mathrm{O} \rightarrow 2 \mathrm{RbOH}+\mathrm{H}_2 \\ \xrightarrow{\mathrm{Li} \lt \mathrm{Na} \lt \mathrm{K} \lt \mathrm{Rb} \lt \mathrm{Cs}}\end{gathered}$
As we go down the group reactivity with $\mathrm{H}_2 \mathrm{O}$ increases.

Topic: Chemistry, s Block Elements, JEE Main
Which of the following reagent can be used to carry out this synthesis of glycol?

Options:
A Benedict reagent
B Baeyer's reagent
C Barfoed reagent
D Seliwanoff reagent

The correct answer is:
Baeyer's reagent

Solution:
Explanation: Cold dilute alkaline solution of Bayer's reagent can be used to carry out this synthesis of glycol.

Topic: Chemistry, Alcohols Phenols and Ethers, JEE Main
Which of the following reagent is used for the following reaction?

CH3CH2CH3 →?CH3CH2CHO

Options:
A Copper at high temperature and pressure
B Manganese acetate
C Molybdenum oxide
D Potassium permanganate

The correct answer is:
Molybdenum oxide

Solution:
CH3-CH2-CH3 →Mo2O3CH3-CH2-CH=O

The reagent used will be Mo2O3 (molybdenum oxide) as this reagent always used to oxidise alkanes to aldehyde. So, it is widely used as an oxidation catalyst for acid-mediated catalytic reactions.

Topic: Chemistry, Aldehydes and Ketones, JEE Main, JEE Main 2021 (24 Feb Shift 1)
Which of the following reagents can be used to oxidize primary alcohols to aldehydes?

Options:
A $\mathrm{KMnO}_4$
B PCC (Pyridinium chlorochromate)
C $\mathrm{LiAlH}_4$
D $\mathrm{H}_2 / \mathrm{Pd}$

The correct answer is:
PCC (Pyridinium chlorochromate)

Solution:
PCC (Pyridinium chlorochromate)
Explanation: PCC is a mild oxidizing agent that selectively oxidizes primary alcohols to aldehydes without further oxidation to carboxylic acids.

Topic: Chemistry, Alcohols Phenols and Ethers, JEE Main
Which of the following reagents can be used to prepare an amide from a carboxylic acid?

Options:
A $\mathrm{SOCl}_2$ followed by $\mathrm{NH}_3$
B $\mathrm{H}_2 / \mathrm{Pd}$
C $\mathrm{KMnO}_4$
D $\mathrm{NaBH}_4$

The correct answer is:
$\mathrm{H}_2 / \mathrm{Pd}$

Solution:
Reaction with ammonia
Explanation: Carboxylic acids react with ammonia $\left(\mathrm{NH}_3\right)$ or amines to form amides. The reaction usually involves heating to remove water and form the amide bond.

Topic: Chemistry, Amines, JEE Main
Which of the following reagents can form a hydrazone with alkanone?

Options:
A $\mathrm{NH}_3 \mathrm{OHCl}$
B $\mathrm{PhNHNH}_2$
C $\mathrm{NH}_2 \mathrm{NHCONH}_2$
D $HCN$

The correct answer is:
$\mathrm{PhNHNH}_2$

Solution:
Hydrazines react with alkanones to give an addition-elimination reaction and hydrazones are obtained.

Topic: Chemistry, Aldehydes and Ketones, JEE Main
Which of the following reagents is commonly used to prepare ethylene glycol from ethylene?

Options:
A $\mathrm{H}_2 / \mathrm{Pd}$
B $\mathrm{OsO}_4$ (Osmium tetroxide)
C $\mathrm{KMnO}_4$ (Potassium permanganate)
D $\mathrm{H}_2 \mathrm{SO}_4$ (Sulfuric acid)

The correct answer is:
$\mathrm{KMnO}_4$ (Potassium permanganate)

Solution:
$\mathrm{KMnO}_4$ (Potassium permanganate)
Explanation: Ethylene glycol is commonly prepared by the hydroxylation of ethylene using a dilute solution of potassium permanganate, which adds hydroxyl groups to the double bond.

Topic: Chemistry, Alcohols Phenols and Ethers, JEE Main
Which of the following reagents is commonly used to prepare oxiranes from alkenes?

Options:
A $\mathrm{H}_2 / \mathrm{Pd}$
B $\mathrm{Br}_2 / \mathrm{CCl}_4$
C mCPBA (meta-Chloroperoxybenzoic acid)
D $\mathrm{NaBH}_4$

The correct answer is:
mCPBA (meta-Chloroperoxybenzoic acid)

Solution:
mCPBA (meta-Chloroperoxybenzoic acid)
Explanation: mCPBA is a peracid commonly used in the epoxidation of alkenes to form oxiranes (epoxides).

Topic: Chemistry, Alcohols Phenols and Ethers, JEE Main
Which of the following reagents is used to distinguish acetone and acetophenone

Options:
A $\mathrm{NaHSO}_3$
B Grignard reagent
C $\mathrm{Na}_2 \mathrm{SO}_4$
D $\mathrm{NH}_4 \mathrm{Cl}$

The correct answer is:
$\mathrm{NaHSO}_3$

Solution:
Acetone forms sodium bisulphate adduct but acetophenone does not. Aromatic ketones do not gives addition product with
$\mathrm{NaHSO}_3$

Topic: Chemistry, Aldehydes and Ketones, JEE Main
Which of the following reagents may be used to distinguish between phenol and benzoic acid ?

Options:
A
Tollen's reagent

B
Molisch reagent

C
Neutral $\mathrm{FeCl}_3$

D
Aqueous $\mathrm{NaOH}$

The correct answer is:
Neutral $\mathrm{FeCl}_3$

Solution:
Phenol gives violet coloured comlex compound with neutral $\mathrm{FeCl}_3$, benzoic acid gives pale dull yellow ppt. with neutral $\mathrm{FeCl}_3$

Topic: Chemistry, General Organic Chemistry, JEE Main, JEE Main 2011
Which of the following reagents may not be used to convert alkyl chlorides and alkyl bromides into alkylfluorides?

Options:
A Hg2F2
B SbF5
C AgF
D CaF2

The correct answer is:
CaF2

Solution:
It is an example of Swart reaction used to prepare fluoro alkanes.
R-BrâHgF2 or SbF5 or AgFR-F

Topic: Chemistry, Haloalkanes and Haloarenes, JEE Main
Which of the following reagents / reactions will convert 'A' to 'B'?

Options:
A PCC oxidation
B Ozonolysis
C BH3,H2O2/-OH followed by PCC oxidation
D HBr, hydrolysis followed by oxidation by K2Cr2O7.

The correct answer is:
BH3,H2O2/-OH followed by PCC oxidation

Solution:
First step of the reaction involves hydroboration oxidation and second step involves oxidation of primary alcoholic group by using PCC.

Topic: Chemistry, Hydrocarbons, JEE Main, JEE Main 2022 (24 Jun Shift 2)
Which of the following reagent(s) used for the conversion?

Options:
A
glycol/$\mathrm{LiAlH}_4 / \mathrm{H}_3 \mathrm{O}^{+}$

B
glycol/ $\mathrm{NaH} / \mathrm{H}_3 \mathrm{O}^{+}$

C
$\mathrm{LiAlH}_4$

D
$\mathrm{NaBH}_4$

The correct answer is:
glycol/$\mathrm{LiAlH}_4 / \mathrm{H}_3 \mathrm{O}^{+}$

Solution:

Topic: Chemistry, Alcohols Phenols and Ethers, JEE Main, JEE Main 2013 (25 Apr Online)
Which of the following reagents will be able to distinguish between 1-butyne and 2-butyne?

Options:
A $\mathrm{NaNH}_2$
B $\mathrm{HCl}$
C $\mathrm{O}_2$
D $\mathrm{Br}_2$

The correct answer is:
$\mathrm{NaNH}_2$

Solution:
$\mathrm{NaNH}_2$ is used to distinguish between 1-butyne and 2-butyne.
$$
\begin{aligned}
&\begin{array}{r}
\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{C} \equiv \mathrm{CH} \stackrel{\mathrm{NaNH}_2}{\longrightarrow} \mathrm{CH}_3 \mathrm{CH}_2 \mathrm{C} \equiv \mathrm{CNa} \\
+\frac{1}{2} \mathrm{H}_2 \uparrow
\end{array}\\
&\mathrm{CH}_3-\mathrm{C} \equiv \mathrm{C}-\mathrm{CH}_3 \stackrel{\mathrm{NaNH}_2}{\longrightarrow} \text { No reaction }
\end{aligned}
$$

Topic: Chemistry, Hydrocarbons, NEET, NEET 2012 (Mains)
Which of the following reasons in mainly responsible for graft rejection in transplantation of organs?

Options:
A Inability of recipient to differentiate between 'self and 'non-self' tissues/cells
B Humoral immune response only
C Auto-immune response
D Cell-mediated response

The correct answer is:
Cell-mediated response

Solution:
During organ transplantation, the graft rejection takes place due to cell mediated response, in which T-cell controls the identification of Self from Non-self.
This rejection can be prevented by Immuno-suppressive agent i.e., Cyclosporin-A.

Topic: Biology, Human Health and Diseases, NEET, NEET 2022 (Phase 2)