List of top Chemistry Questions asked in JEE Main

Match List I with List II :

LIST I Isomeric pairs		LIST II Type of isomers
A	Propanamine and N-Methylethanamine	I	Metamers
B	Hexan-2-one and Hexan-3-one	II	Positional isomers
C	Ethanamide and Hydroxyethanimine	II	Functional isomers
D	o-nitrophenol and p-nitrophenol	IV	Tautomers

Choose the correct answer from the options given below:

The metal which is extracted by oxidation and subsequent reduction from its ore is:

The energy of an electron in the first Bohr orbit of hydrogen atom is $-2.18×10^{-18}J$. Its energy in the third Bohr orbit is ____.

A litre of buffer solution contains $01$ mole of each of $NH _3$ and $NH _4 CL$ On the addition of $002$ mole of $HCl$ by dissolving gaseous $HCl$, the $pH$ of the solution is found to be ____ $\times 10^{-3}$ (Nearest integer) [Given : $pK _5\left( NH _3\right)=4745$ $ \log 2=0301$ $\log 3=0477$ $T =298 K ]$

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

From the figure of column chromatography given below, identify incorrect statements

A. Compound 'c' is more polar than 'a' and 'b'
B. Compound 'a' is least polar
C. Compound 'b' comes out of the column before 'c' and after 'a'
D. Compound 'a' spends more time in the column
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

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

Major product of the following reaction is

It is observed that characteristic $X$-ray spectra of elements show regularity When frequency to the power " $n$ " ie $v^n$ of $X$-rays emitted is plotted against atomic number " $Z$ ", following graph is obtained

The increasing order of metallic character

The wave function $(\Psi)$ of $2 s$ is given by $\Psi_{2 n }=\frac{1}{2 \sqrt{2 \pi}}\left(\frac{1}{a_0}\right)^{1 / 2}\left(2-\frac{r}{a_0}\right) e^{-\frac{r}{2 a_0}}$ At $r=r_0$, radial node is formed Thus, $r_0$ in terms of $a_0$

Given below are two statements: one is labeled as Assertion (A) and the other is labeled as Reason (R).
Statement-1: According to Bohr’s Model, angular momentum is Quantized for stationary orbits.
Statement-2: Bohr’s Model doesn’t follow Heisenberg’s Uncertainty Principle.
In the light of the above statements, write the detailed answer:

The number of species from the following carrying a single lone pair on central atom Xenon is ______ .
XeF₅⁺, XeO₃, XeO₂F₂, XeF₅^-, XeO₃F₂, XeOF₄, XeF₄

The correct relationships between unit cell edge length ‘a’ and radius of sphere ‘r’ for face-centred and body-centred cubic structures respectively are:

Number of compounds giving (i) red colouration with ceric ammonium nitrate and also (ii) positive iodoform test from the following is_____

The correct order of melting points of dichlorobenzenes is

Compound $( X )$ undergoes following sequence of reactions to give the Lactone $( Y )$

$20 \,mL$ of $01 \,M \,NH _4 OH$ is mixed with $40\, mL$ of $005\, M \,HCl$ The $pH$ of the mixture is nearest to: (Given: $K _{ b }\left( NH _4 OH \right)=1 \times 10^{-5}, \log 2=030$, $\log 3=048, \log 5=069, \log 7=084$, $\log 11=104$ )

600 mL of 0.04 M HCl is mixed with 400 mL of 0.02 M H₂SO₄. Find out the pH of resulting solution (Nearest integer).

4.5 moles each of hydrogen and iodine is heated in a sealed ten litre vessel. At equilibrium, 3 moles of HI were found. The equilibrium constant for H₂(g) + I₂(g) ⇋ 2HI(g) 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:

The magnetic moment of a transition metal compound has been calculated to be 3.87 B.M. The metal ion is

1 L, 0.02 M solution of [Co(NH₃)₅SO₄]Br is mixed with 1 L, 0.02 M solution of [Co(NH₃)₅Br]SO₄. The resulting solution is divided into two equal parts (X) and treated with excess of AgNO₃ solution and BaCl₂ solution respectively as shown below:
1 L Solution (X) + AgNO₃ solution (excess) → Y
1 L Solution (X) + BaCl₂ solution (excess) → Z
The number of moles of Y and Z respectively are

Some amount of dichloromethane $\left( CH _2 Cl _2\right)$ is added to $671.141 \,mL$ of chloroform $\left( CHCl _3\right)$ to prepare $2.6 \times 10^{-3} M$ solution of $CH _2 Cl _2$ (DCM) The concentration of DCM is ______$ppm$ (by mass) Given: atomic mass : $C =12$ $H =1$ $Cl =35.5$ density of $CHCl _3=1.49\, g \,cm ^{-3}$