List of top Chemistry Questions asked in JEE Main

Number of unpaired electron in highest occupied molecular orbital of following species is :\(N_2, N ^+_ 2 , O_2, O^+_ 2 \) ? 

Given below are two statements:
Statement-I: Pure Aniline and other arylamines are usually colourless.
Statement-II: Arylamines get coloured on storage due to atmospheric reduction
In the light of the above statements, choose the most appropriate answer from the options given below:

The starting material for convenient preparation of deuterated hydrogen peroxide \(\left(D_2 O _2\right)\) in laboratory is :

How many reactions are non-spontaneous at 300 K. For independent reaction ΔH & ΔS values are given.
Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: In an Ellingham diagram, the oxidation of carbon to carbon monoxide shows a negative slope with respect to temperature
Reason R: CO tends to get decomposed at higher temperature
In the light of the above statements, choose the correct answer from the options given below
Which of the following statements is correct about freons?

Match List I with List II:

LIST I (Type) LIST II (Name)
(P) Antifertility drugs(A) Norethindrone 
(Q) Antihistamines(B) Seldane
(R) Tranquilizers(C) Meprobamate
(S) Antibiotics(D) Penicillin

Choose the correct answer from the options given below:

Compound A from the following reaction sequence is 
Br2 , C S 2 0 − 5 ° C 0 − 5 ° 𝐶 → 𝐵 𝑟 2 , 𝐶 𝑆 2 B. N a N O 2 / H C l

For which of the following aqueous ion, spin only magnetic moment is 3.87 BM?

Which one amongst the following are good oxidizing agents?
(A) \( \text{Sm}^{\text{2+}}\)
(B) \(\text{Ce}^{\text{2+}}\)
(C)\( \text{Ce}^{\text{4+}}\)
(D) \(\text{Tb}^{\text{4+}}\)
Choose the most appropriate answer from the options given below:

Statement-I: Noradrenaline is one of the neurotransmitter. 

Statement-II: Low level of noradrenaline is not cause of depression in humans.

In light of the above statements, choose the correct answer from the options given below

\(H_2O_2\) behave like reducing agent in which of the following reactions:

S1: Be+2 has higher SRP than other alkaline earth metals.
S2: Be+2 has higher hydration energy and greater △aH (atomisation enthalpy) than other alkaline earth metals.

Match the following:
Column-IColumn-II
(A) Zone refining(P) pig iron
(B) Electrolysis(Q) Al
(C) Reverberatory furnace(R) Si
(D) Blast furnace(S) Cu
The metal which is extracted by oxidation and subsequent reduction from its ore is:
Freezing point of solution is less than that of pure solvent, which of the following statements are correct ? 
(A) Vapour pressure of solution is less than that of pure solvent 
(B) Vapour pressure of solution is greater than that of pure solvent 
(C) Only solvent molecules will freeze 
(D) Only solute molecules will freeze
\([Co(NH_3)_6]^{3+} \text{is} \) ________\(\text{hybridised and}\)________
An \( \alpha \)-particle, a proton, and an electron have the same kinetic energy. Which one of the following is correct in case of their De-Broglie wavelength:

The effect of addition of helium gas to the following reaction in equilibrium state, is : \(PCl _5( g ) \rightleftharpoons PCl _3( g )+ Cl _2( g )\)

\(A(g) ⇋ 2B(g) + C(g)\)
For the given reaction, if the initial pressure is 450 mm Hg and the pressure at time t is 720 mm Hg at a constant temperature T and constant volume V. The fraction of A(g) decomposed under these conditions is \(x × 10^{–1}\). The value of x is _____ . (nearest integer)
In alkaline medium, the reduction of permanganate anion involves a gain of _____ electrons.
The electron in the \(n^{th}\) orbit of \(Li^{2+}\) is excited to \((n + 1)\) orbit using the radiation of energy \(1.47 × 10^{–1}J \) (as shown in the diagrarn). The value of n is ______ .
Given: \(R_H = 2.18 × 10^{–18} J\).
The number of incorrect statement/s from the following is ____ .
A. The successive half lives of zero order reactions decreases with time.
B. A substance appearing as reactant in the chemical equation may not affect the rate of reaction.
C. Order and molecularity of a chemical reaction can be a fractional number.
D. The rate constant units of zero and second order reaction are mol L–1s–1 and mol–1 Ls–1 respectively.
During the reaction of permanganate with thiosulphate, the change in oxidation of manganese occurs by value of 3. Identify which of the below medium will favour the reaction
The number of endothermic process/es from the following is _____ .
A. \(I_2 (g) → 2I (g)\)
B. \(HCl (g) → H(g) + Cl (g)\)
C. \(H_2O(l) → H_2O (g)\)
D. \(C(s) + O_2 (g) → CO_2 (g)\)
E. Dissolution of ammonium chloride in water.