List of top Chemistry Questions asked in JEE Main

The elements of Group 13 with highest and lowest first ionisation enthalpies are respectively:

‘X’ is the number of electrons in $ t_2g $ orbitals of the most stable complex ion among $ [Fe(NH_3)_6]^{3+} $, $ [Fe(Cl)_6]^{3-} $, $ [Fe(C_2O_4)_3]^{3-} $ and $ [Fe(H_2O)_6]^{3+} $. The nature of oxide of vanadium of the type $ V_2O_x $ is: 
 

Consider the following plots of log of rate constant $ k (log k)$ vs $ \frac{1}{T} $ for three different reactions. The correct order of activation energies of these reactions is:

Choose the correct answer from the options given below:

The correct order of $ [FeF_6]^{3-} $, $ [CoF_6]^{3-} $,$ [Ni(CO)_4] $ and $ [Ni(CN)_4]^{2-} $ complex species based on the number of unpaired electrons present is:

Match List-I with List-II: List-I

A dipeptide, “x”, on complete hydrolysis gives “y” and “z”; “y” on treatment with aqueous HNO$_2$, produces lactic acid. On the other hand, “z” on heating gives the following cyclic molecule.

Based on the information given, the dipeptide X is:

The correct order of basicity for the following molecules is:

The incorrect relationship in the following pairs in relation to ionisation enthalpies is:
Total number of molecules/species from the following which will be paramagnetic is ________________________. \[ O_2, O_2^+, O_2^-, NO, NO_2, CO, K_2[NiCl_4], [Co(NH_3)_6]Cl_3, K_2[Ni(CN)_4] \]
The spin-only magnetic moment (\(\mu\)) value (B.M.) of the compound with the strongest oxidising power among \(Mn_2O_3\), \(TiO\), and \(VO\) is ________________________ B.M. (Nearest integer).
Arrange the following in increasing order of solubility product: \[ {Ca(OH)}_2, {AgBr}, {PbS}, {HgS} \]
The purification method based on the following physical transformation is: \[ {Solid} \xrightarrow{{Heat}} {Vapour} \xrightarrow{{Cool}} {Solid} \]
An ideal gas undergoes a cyclic transformation starting from point A and coming back to the same point by tracing the path A→B→C→D→A as shown in the three cases below.
ideal gas undergoes a cyclic transformation
Choose the correct option regarding \(\Delta U\):
Match List - I with List - II.
[CoF6]3
Choose the correct answer from the options given below:
Identify the inorganic sulphides that are yellow in colour: (A) \( ({NH}_4)_2{S} \)
(B) \( {PbS} \)
(C) \( {CuS} \)
(D) \( {As}_2{S}_3 \)
(E) \( {As}_2{S}_5 \)
Choose the correct answer from the options given below:
Given below are two statements: Statement (I): According to the Law of Octaves, the elements were arranged in the increasing order of their atomic number.
Statement (II): Meyer observed a periodically repeated pattern upon plotting physical properties of certain elements against their respective atomic numbers. In the light of the above statements, choose the correct answer from the options given below:
The element that does not belong to the same period of the remaining elements (modern periodic table) is:
Heat treatment of muscular pain involves radiation of wavelength of about 900 nm. Which spectral line of H atom is suitable for this? Given: Rydberg constant \( R_H = 10^5 \, \text{cm}^{-1} \), \( h = 6.6 \times 10^{-34} \, \text{J s} \), and \( c = 3 \times 10^8 \, \text{m/s} \)
The incorrect statements among the following is:
CrCl\(_3\).xNH\(_3\) can exist as a complex. 0.1 molal aqueous solution of this complex shows a depression in freezing point of 0.558°C. Assuming 100\% ionization of this complex and coordination number of Cr is 6, the complex will be:
The d-electronic configuration of an octahedral Co(II) complex having a magnetic moment of 3.95 BM is:
What amount of bromine will be required to convert 2 g of phenol into 2, 4, 6-tribromophenol? (Given molar mass in g mol\(^{-1}\) of C, H, O, Br are 12, 1, 16, 80 respectively)
The correct set of ions (aqueous solution) with the same colour from the following is:

Match the LIST-I with LIST-II: 

 


Choose the correct answer from the options given below :

If 1 mM solution of ethylamine produces pH = 9, then the ionization constant (\(K_b\)) of ethylamine is \(10^{-x}\).

The value of x is             (nearest integer).
The degree of ionization of ethylamine can be neglected with respect to unity.