List of top Chemistry Questions asked in JEE Main

$\text{The hydrogen electrode is dipped in a solution of pH = 3 at } 25^{\circ}\text{C. The potential of the electrode will be } -\_\_\_\_\_ \times 10^{-2} \text{ V.}$
$\left( \frac{2.303RT}{F} = 0.059 \, \text{V} \right)$

Identity the incorrect pair from the following:

Total number of compounds with Chiral carbon atoms from following is ________.

$\text{CH}_3 - \text{CH}_2 - \text{CH(NO}_2\text{) - COOH} \\ \text{CH}_3 - \text{CH}_2 - \text{CHBr - CH}_2 - \text{CH}_3 \\ \text{CH}_3 - \text{CH(I) - CH}_2 - \text{NO}_2 \\ \text{CH}_3 - \text{CH}_2 - \text{CH(OH) - CH}_2\text{OH} \\$

$9.3 \, \text{g of aniline is subjected to reaction with excess of acetic anhydride to prepare acetanilide. The mass of acetanilide produced if the reaction is 100\% completed is } \_\_\_\_\_ \times 10^{-1} \, \text{g.} \\ \text{(Given molar mass in g mol}^{-1}\text{) N: 14, O: 16, C: 12, H: 1}$

The final product A, formed in the following reaction sequence is:

The Lassaigne’s extract is boiled with dil HNO\(_3\) before testing for halogens because

Match List-I with List-II
\[ \begin{array}{|c|c|} \hline \text{List-I (Species)} & \text{List-II (Electronic distribution)} \\ \hline \text{(A) Cr}^{+2} & \text{(I) } 3d^8 \\ \text{(B) Mn}^{+} & \text{(II) } 3d^3 4s^1 \\ \text{(C) Ni}^{+2} & \text{(III) } 3d^4 \\ \text{(D) V}^{+} & \text{(IV) } 3d^5 4s^1 \\ \hline \end{array} \]

Given below are two statements:
Statement-I: The gas liberated on warming a salt with dil H₂SO₄, turns a piece of paper dipped in lead acetate into black, it is a confirmatory test for sulphide ion.
Statement-II: In statement-I the colour of paper turns black because of formation of lead sulphite. In the light of the above statements, choose the most appropriate answer from the options given below:

Following is a confirmatory test for aromatic primary amines. Identify reagent (A) and (B)

In the given reactions identify the reagent A and reagent B

Given below are the two statements: one is labelled as Assertion (A) and the other is labeled as Reason (R).
Assertion (A): There is a considerable increase in covalent radius from N to P. However from As to Bi only a small increase in covalent radius is observed.
Reason (R): covalent and ionic radii in a particular oxidation state increases down the group.
In the light of the above statement, choose the most appropriate answer from the options given below:

Given below are two statement one is labeled as Assertion (A) and the other is labeled as Reason (R).
Assertion (A): CH₂ = CH – CH₂ – Cl is an example of allyl halide
Reason (R): Allyl halides are the compounds in which the halogen atom is attached to sp² hybridised carbon atom.
In the light of the two above statements, choose the most appropriate answer from the options given below

The compound formed by the reaction of ethanal with semicarbazide contains _____number of nitrogen atoms.

Which of the following statements is not correct about rusting of iron?

Example of vinylic halide is

The rate of a first order reaction is \( 0.04 \, \text{mol} \, \text{L}^{-1} \, \text{s}^{-1} \) at 10 minutes and \( 0.03 \, \text{mol} \, \text{L}^{-1} \, \text{s}^{-1} \) at 20 minutes after initiation. Half-life of the reaction is \( \_\_\_\_ \) minutes. (Given \( \log 2 = 0.3010, \, \log 3 = 0.4771 \))

The technique used for purification of steam volatile water immiscible substance is:

Structure of 4-Methylpent-2-enal is

\[ 2 \text{MnO}_4^{-} + b \text{I}^{-} + c \text{H}_2\text{O} \rightarrow x \text{I}_2 + y \text{MnO}_2 + z \text{OH}^{-} \]
If the above equation is balanced with integer coefficients, the value of \( z \) is \( \_\_\_\_\_\_ \).

The pH at which Mg(OH)\(_2\) \([K_{sp} = 1 \times 10^{-11}]\) begins to precipitate from a solution containing 0.10 M Mg\(^{2+}\) ions is \( \_\_\_\_ \).

How many of the following vitamins are stored in Human Body?
A, B, C, D, E, K?

The order of relative stability of the contributing structure is:

Choose the correct answer from the options given below:

On a thin layer chromatographic plate, an organic compound moved by 3.5 cm, while the solvent moved by 5 cm. The retardation factor of the organic compound is \( \_\_\_\_ \times 10^{-1} \).

Choose the correct statements from the following:
A Ethane-1,2-diamine is a chelating ligand.
B Metallic aluminium is produced by electrolysis of aluminium oxide in presence of cryolite.
C Cyanide ion is used as a ligand for leaching of silver.
D Phosphine acts as a ligand in Wilkinson catalyst.
E The stability constants of \( \text{Ca}^{2+} \) and \( \text{Mg}^{2+} \) are similar to EDTA complexes.

Choose the correct option having all the elements with \( d^{10} \) electronic configuration from the following: