List of top Chemistry Questions asked in JEE Main

The radius of the $2^{\text {nd }}$ orbit of $Li ^{2+}$ is $x$. The expected radius of the $3^{\text {rd }}$ orbit of $Be ^{3+}$ is

Enthalpies of formation of $CCl _4( g ), H _2 O ( g ), CO _2( g )$ and $HCl ( g )$ are $-105,-242,-394$ and $-92\, kJ$ mol $^{-1}$ respectively The magnitude of enthalpy of the reaction given below is ___$kJ \, mol ^{-1}$ (nearest integer) $CCl _4( g )+2 H _2 O ( g ) \rightarrow CO _2( g )+4 HCl ( g )$

Based on the given figure, the number of correct statement/s is/are _______

A. Surface tension is the outcome of equal attractive and repulsive forces acting on the liquid molecule in bulk
B. Surface tension is due to uneven forces acting on the molecules present on the surface
C. The molecule in the bulk can never come to the liquid surface
D. The molecules on the surface are responsible for vapour pressure if the system is a closed system

Least stable Hydride is?

Photochemical smog found mainly in

Which of the following acts as a stabilizer in the decomposition of H₂O₂?

In which of the following options the species changes from paramagnetic to diamagnetic and bond order increases.

Match List I with List II

LIST I		LIST II
A	Cobalt catalyst	I	$(H_2+Cl_2)$ production
B	Syngas	II	Water gas production
C	Nickel catalyst	III	Coal gasification
D	Brine solution	IV	Methanol production

Choose the correct answer from the options given below:

Some drugs bind to a site other than, theactive site of an enzyme This site is knownas

Which one of the following reactions does not occur during extraction of copper?

The sum of number of lone pairs of electrons present on the central atoms of $XeO _3, XeOF _4$ and $XeF _6$ is_____

The equilibrium composition for the reaction PCl₃ + Cl₂ ⇌ PCI5, at 298 K is given below.
[PCl₃]_eq = 0.2 mol L^-
[Cl₂]eq = 0.1 mol L^-1,
[PCl₅]_eq = 0.40 mol L^-1
If 0.2 mol of Cl₂ is added at the same temperature, the equilibrium concentrations of PCl5 is ___ × 10^-2 mol L^-1
Given: K_c for the reaction at 298 K is 20

For micelle formation, which of the following statements are correct?
(A) Micelle formation is an exothermic process
(B) Micelle formation is an endothermic process
(C) The entropy change is positive
(D) The entropy change is negative

Match the columns Column I Column II (a) Biodegradable (p) polyacrylonitrie (b) Synthetic (q) PHBV (c) Natural (r) dacron (d) Polyester (s) Rubber

What happens when lyophilic sol is added to lyophobic sol. prevention from coagulation precipitation emulsion electrophoresis

Given below are two statements: one is labeled as Assertion (A) and the other is labeled as Reason (R).
Assertion (A): Acidic nature follows the order:

Reason (R): F is a better electron-withdrawing group than Cl
In the light of the above statements, write the detailed answer:

Read the following two statements:
Statement I: Potassium dichromate is used in volumetric analysis.
Statement II: $K_2Cr_2O_7$ is more soluble in water than $Na_2Cr_2O_7$

2[Au(CN)₂]^– + Zn $\to$ [Zn(CN)₄]^2– + 2Au$\downarrow$ is which of these
(A) Redox reaction
(B) Displacement reaction
(C) Combination reaction
(D) Decomposition reaction

During bleeding from cut $FeCl_3$ is used to stop bleeding as

Select correct statements about lead storage battery:

Match List I with List II

List I		List II
A	Tranquilizers	i	Anti blood clotting
B	Aspirin	ii	Salvarsan
C	Antibiotic	iii	Antidepressant drugs
D	Antiseptic	iv	Soframicine

Choose the correct answer from the options given below:

Match the terms in Column-I with their description in Column-II and choose the correct option:

Column I (Chemical reactions)		Column II (Enzymes used)
(i)	Glucose → CO₂+ Ethanol	a	Pepsin
(ii)	Sucrose→Glucose + Fructose	b	Diastase
(iii)	Starch →Maltose	c	Zymase
(iv)	Protein→Amino acids	d	Invertase

Stabilizer used for concentrating sulphide ore

Match List I with List II:

List I (Mixture)		List II (Separation Technique)
A	CHCl₃+C₆H₅NH₂	i	Steam distillation
B	C₆H₁₄+C₅H₁₂	ii	Differential extraction
C	C₆H₅NH₂+H₂O	iii	Distillation
D	Organic compound in H₂O	iv	Fractional distillation

The reaction of $H _2 O _2$ with potassium permanganate in acidic medium leads to the formation of mainly: