List of top Chemistry Questions asked in JEE Main

An octahedral complex with the formula \(\text{CoCl}_3n\text{NH}_3\) upon reaction with excess of \(\text{AgNO}_3\) solution gives 2 moles of \(\text{AgCl}\). Consider the oxidation state of Co in the complex is \(x\). The value of "x + n" is ______.

For the given hypothetical reactions, the equilibrium constants are as follows:
\[ X \rightleftharpoons Y; \, K_1 = 1.0 \]
\[ Y \rightleftharpoons Z; \, K_2 = 2.0 \]
\[ Z \rightleftharpoons W; \, K_3 = 4.0 \]
The equilibrium constant for the reaction
\[ X \rightleftharpoons W\]
is:

Match List-I with List-II.

List-I (Name of the test)	List-II (Reaction sequence involved) [M is metal]
(A) Borax bead test	I
(B) Charcoal cavity test	II
(C) Cobalt nitrate test	III
(D) Flame test	IV

Choose the correct 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: The stability order of \(+1\) oxidation state of Ga, In, and Tl is \( \text{Ga}<\text{In}<\text{Tl} \).
Reason R: The inert pair effect stabilizes the lower oxidation state down the group.
In the light of the above statements, choose the correct answer from the options given below:

Combustion of glucose (\(C_6H_{12}O_6\)) produces \(CO_2\) and water. The amount of oxygen (in g) required for the complete combustion of \(900 \, \text{g}\) of glucose is:
\([ \text{Molar mass of glucose in g mol}^{-1} = 180 ]\)

Which among the following compounds will undergo fastest \(S_N2\) reaction?

Given below are two statements:
Statement I:

IUPAC name of Compound A is 4-chloro-1, 3-dinitrobenzene.
Statement II:

IUPAC name of Compound B is 4-ethyl-2-methylaniline.
In the light of the above statements, choose the most appropriate answer from the options given below:

Wavenumber for a radiation having $5800 \, \mathring{A}$ wavelength is $x \times 10 \, \text{cm}^{-1}$. The value of $x$ is _________

Total number of unpaired electrons in the complex ion [Co(NH$_3$)$_6$]$^{3+}$ and [NiCl$_4$]$^{2-}$ is

Total number of aromatic compounds among the following compounds is _______.

Two moles of benzaldehyde and one mole of acetone under alkaline conditions using aqueous NaOH after heating gives $x$ as the major product. The number of $\pi$ bonds in the product $x$ is ................

Total number of optically active compounds from the following is _______.

Number of molecules having bond order 2 from the following molecule is ...................
$C_2, O_2, Be_2, Li_2, Ne_2, N_2, He_2$

$\Delta_{vap}H^\circ$ for water is $+40.49 \, \text{kJ mol}^{-1}$ at 1 bar and $100^\circ\text{C}$. Change in internal energy for this vaporisation under same condition is .............. kJ mol$^{-1}$. (Integer answer)
(Given R = 8.3 J K$^{-1}$ mol$^{-1}$)

Match List-I with List-II.

List-I (Complex ion)	List-II (Spin only magnetic moment in B.M.)
(A) [Cr(NH$_3$)$_6$]$^{3+}$	(I) 4.90
(B) [NiCl$_4$]$^{2-}$	(II) 3.87
(C) [CoF$_6$]$^{3-}$	(III) 0.0
(D) [Ni(CN)$_4$]$^{2-}$	(IV) 2.83

Choose the correct answer from the options given below:

Given below are two statements:
Statement (I) : Fusion of MnO$_2$ with KOH and an oxidising agent gives dark green K$_2$MnO$_4$.
Statement (II) : Manganate ion on electrolytic oxidation in alkaline medium gives permanganate ion.
In the light of the above statements, choose the correct answer from the options given below.

Given below are two statements :
Statement (I) : Kjeldahl method is applicable to estimate nitrogen in pyridine.
Statement (II) : The nitrogen present in pyridine can easily be converted into ammonium sulphate in Kjeldahl method.
In the light of the above statements, choose the correct answer from the options given below.

The correct sequence of acidic strength of the following aliphatic acids in their decreasing order is: $CH_3CH_2COOH$, $CH_3COOH$, $CH_3CH_2CH_2COOH$, $HCOOH$

Given below are two statements:
Statement (I) : A Buffer solution is the mixture of a salt and an acid or a base mixed in any particular quantities.
Statement (II) : Blood is naturally occurring buffer solution whose pH is maintained by $H_2CO_3/HCO_3^-$ concentrations.
In the light of the above statements, choose the correct answer from the options given below.

The equilibrium $\mathrm{Cr_2O_7^{2-}} \rightleftharpoons 2\mathrm{CrO_4^{2-}}$ is shifted to the right in:

IUPAC name of following hydrocarbon (X) is :

Identify the incorrect statements about group 15 elements:
(A) Dinitrogen is a diatomic gas which acts like an inert gas at room temperature.
(B) The common oxidation states of these elements are −3, +3 and +5.
(C) Nitrogen has unique ability to form p$\pi$-p$\pi$ multiple bonds.
(D) The stability of +5 oxidation states increases down the group.
(E) Nitrogen shows a maximum covalency of 6.
Choose the correct answer from the options given below.

Match List-I with List-II.

List-I (Test)	List-II (Identification)
(A) Bayer's test	(I) Phenol
(B) Ceric ammonium nitrate test	(II) Aldehyde
(C) Phthalein dye test	(III) Alcoholic-OH group
(D) Schiff's test	(IV) Unsaturation

Choose the correct answer from the options given below:

Match List-I with List-II.

Choose the correct answer from the options given below :

Given below are two statements:
Statement (I) : S$_N$2 reactions are 'stereospecific', indicating that they result in the formation only one stereo-isomers as the product.
Statement (II) : S$_N$1 reactions generally result in formation of product as racemic mixtures.
In the light of the above statements, choose the correct answer from the options given below :