List of top Chemistry Questions asked in JEE Main

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
\([Co(NH_3)_6]^{3+} \text{is} \) ________\(\text{hybridised and}\)________
Which of the following statements is correct about freons?
Which of the following complex will show largest splitting of $d$-orbitals?
The metal which is extracted by oxidation and subsequent reduction from its ore is:

\(H_2O_2\) 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.

Correct order of strength of H-bond in the following -:
(A) Liquid water
(B) Ice 
(C) Impure water

\(K_2Cr_2O_7\) paper acidified with dil. \(H_2SO_4\) turns green when exposed to :
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

Graph of X-ray frequency (v)n v/s atomic number (Z) is linear. Find the value of n.

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

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

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:

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

\(A(g) ⇋ 2B(g) + C(g)\)
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.
The difference in the oxidation state of \(Xe\) between the oxidised product of \(Xe\) formed on complete hydrolysis of \(XeF_4\) and \(XeF_4\) is _____ .
An aqueous solution of volume 300 cm3 contains 0.63 g of protein. The osmotic pressure of the solution
at 300 K is 1.29 mbar. The molar mass of the protein is ____ g mol–1.
Given: R = 0.083 L bar K–1 mol–1