List of top Chemistry Questions asked in JEE Main

The number of paramagnetic species among the following is ____B2,Li2,C2,C-2, O22--,O2+ and He2+

40% of HI undergoes decomposition to H2 and I2 at 300 K. ΔG° for this decomposition reaction at one atmosphere pressure is _____ J mol–1. [nearest integer]
(Use R = 8.31 J K–1 mol–1; log 2 = 0.3010, ln 10 = 2.3, log 3 = 0.477)
The moles of methane required to produce 81 g of water after complete combustion is _____ × 10–2 mol. [nearest integer]

An organic compound ‘A’ on reaction with NH3 followed by heating gives compound B. Which on further strong heating gives compound C(C8H5NO2). Compound C on sequential reaction with ethanolic KOH, alkyl chloride and hydrolysis with alkali gives a primary amine. The compound A is :

Fig. Reaction

Consider the above reaction. The number of π electrons present in the product ‘P’ is _____ .

Match List - I with List - II 
List-I (Compound)                                              List-II (Shape)
A \(BrF _5\)                                                                    I bent 
B \(\left[ CrF _6\right]^{3-}\)                                                             II square pyramidal
C \(O _3\)                                                                     III trigonal bipyramidal 
D \(PCl _5\)                                                                    IV octahedral 
Choose the correct answer from the optionsgiven below :
The product formed in the following reaction.
The product formed in the reaction

When the excited electron of a H atom from n = 5 drops to the ground state, the maximum number of emission lines observed are ____.

At 300 K, a sample of 3.0 g of gas A occupies the same volume as 0.2 g of hydrogen at 200 K at the same pressure. The molar mass of gas A is _____ g mol–1. (nearest integer)
Assume that the behaviour of gases as ideal.
(Given: The molar mass of hydrogen (H2) gas is 2.0 g mol–1).
The difference in the reaction of phenol with bromine in chloroform and bromine in water medium is due to :
Phenol on reaction with dilute nitric acid, gives two products. Which method will be most efficient for large scale separation?
The pair, in which ions are isoelectronic with \(Al^{3+}\) is:
Among the following species
N2,N2+,N2−,N22−,O2,O2+,O2−,O22−
the number of species showing diamagnetism is ________.
In the following reaction:
In the reaction compound A and B is
The compound A and B respectively are:
lf the work function of a metal is 6.63 × 10–19 J, the maximum wavelength of the photon required to remove a photoelectron from the metal is ______ nm. (Nearest integer)
[Given : h = 6.63 × 10–34 J s, and c = 3 × 108 m s–1]
The major product in the reaction is:
The major product in the reaction with product2-Methyl prop-1-ene
‘A’ and ‘B’ respectively are: \(A\xrightarrow[(2)Zn-H_2O]{(1)O_3}\)
\(Ethane-1, 2-dicarbaldehyde + Glyoxal/Oxaldehyde\)
\(B \xrightarrow[(2)Zn-H_2O]{(1)O_3}   5 - oxohexanal\)
Which one of the following compounds is inactive towards SN1 reaction?

The major product of the following reaction contains ______ bromine atom(s).

Fig
How many of the following drugs is/are examples(s) of broad-spectrum antibiotics?
Ofloxacin, Penicillin G, Terpineol, Salvarsan.
Two isomers ‘A’ and ‘B’ with molecular formula C4H8 give different products on oxidation with KMnO4/H+ results in effervescence of a gas and gives ketone. The compound ‘A’ is
Incorrect statement for Tyndall effect is:

The number of sp3 hybridised carbons in an acyclic neutral compound with molecular formula C4H5N is ________.

Which of the following sets of quantum numbers is not allowed?

Haemoglobin contains \(0.34\%\) of iron by mass. The number of Fe atoms in \(3.3\) g of haemoglobin is(Given: Atomic mass of Fe is \(56\) u, \(N_A\) = \(6.022 × 1023\) \(mol^{–1}\))