List of top Chemistry Questions asked in JEE Main

At 298 K, the standard reduction potential for Cu²⁺/Cu electrode is 0.34 V. 
Given: Ksp Cu(OH)2 = 1 × 10^-20 
Take \(\frac{2.303RT}{F}\)= 0.059V 
The reduction potential at pH = 14 for the above couple is (-)x x 10^-2 V. 
The value of x is_____.

20 mL of 0.1 M NaOH is added to 50 mL of 0.1 M acetic acid solution. The pH of the resulting solution is____ x 10^-2 (Nearest integer) 
Given: pKa (CH₃COOH) = 4.76 
log 2 = 0.30 
log 3 = 0.48

Bond dissociation energy of "E-H" bond of the " $H _2 E$ " hydrides of group $16$ elements (given below), follows order.
A. $O$ B. $S$ C. $Se$ D. $Te$
Choose the correct from the options given below:

1 L, 0.02 M solution of [Co(NH₃)₅ SO₄]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

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 $a_0$

The most stable carbocation for the following is:

Match List I with List II

List I (Complex)		List II (Hybridization)
A.	Ni(CO)4	I.	sp3
B.	[Cu(NH3)4]2+	II.	dsp2
C.	[Fe(NH3)6]2+	III.	sp3d2
D.	[Fe(H2O)6]2+	IV.	d2sp3

Choose the correct answer from the options given below:

$28.0\, L$ of $CO _2$ is produced on complete combustion of $168 \, L$ gaseous mixture of ethene and methane at $25^{\circ} C$ and $1 \, atm$ Heat evolved during the combustion process is ______$kJ$ Given : $\Delta H _{ c }\left( CH _4\right)=-900 \, kJ\, mol ^{-1}$ $\Delta H _{ c }\left( C _2 H _4\right)=-1400\, kJ \, mol ^{-1}$

When the hydrogen ion concentration $\left[ H ^{+}\right]$changes by a factor of $1000$ , the value of $pH$ of the solution_____

Given below are two statements, one is labelled as Assertion $A$ and the other is labelled as Reason $R$
Assertion A: Carbon forms two important oxides - $CO$ and $CO _2 .CO$ is neutral whereas $CO _2$ is acidic in nature
Reason R : $CO _2$ can combine with water in a limited way to form carbonic acid, while $CO$ is sparingly soluble in water
In the light of the above statements, choose the most appropriate answer from the options given below

Match List I with List II

LIST I (Name of polymer)		LIST II (Uses)
A	Glyptal	I	Flexible pipes
B	Neoprene	II	Synthetic wool
C	Acrilan	III	Paints and Lacquers
D	LDP	IV	Gaskets

Choose the correct answer from the options given below:

Which one among the following metals is the weakest reducing agent?

A. Ammonium salts produce haze in atmosphere 
B. Ozone gets produced when atmospheric oxygen reacts with chlorine radicals
C. Polychlorinated biphenyls act as cleansing solvents 
D. 'Blue baby' syndrome occurs due to the presence of excess of sulphate ions in water 
Choose the correct answer from the options given below:

Statement I : Dipole moment is a vector quantity and by convention it is depicted by a small arrow with tail on the negative centre and head pointing towards the positive centre
Statement II : The crossed arrow of the dipole moment symbolizes the direction of the shift of charges in the molecules.
In the light of the above statements, choose the most appropriate answer from the options given below:

What is the mass ratio of ethylene glycol \((C _2H _6O_2\), molar mass \(62\ g/mol)\) required for making \(500\ g\) of \(0.25\) molal aqueous solution and \(250\ ml\) of \(0.25\) molal aqueous solution?

Given below are two statements, one is labelled as Assertion $A$ and the other is labeled as Reason $R$ 
Assertion A : The alkali metals and their salts impart characteristic colour to reducing flame 
Reason R : Alkali metals can be detected using flame tests 
In the light of the above statements, choose the most appropriate answer from the options given below

Which of the following represents the correct order of metallic character of the given elements?

Given below are two statements:
Statement I : In froth floatation method a rotating paddle agitates the mixture to drive air out of it.
Statement II : Iron pyrites are generally avoided for extraction of iron due to environmental reasons.
In the light of the above statements, choose the correct answer from the options given below:

Match List I with List II

LIST I		LIST II
A	Cobalt catalyst	1	(H2​+Cl2​) production
B	Syngas	2	Water gas production
C	Nickel catalyst	3	Coal gasification
D	Brine solution	4	Methanol production

Choose the correct answer from the options given below:

Number of moles of $AgCl$ formed in the following reaction is

For independent processes at 300K

Process	ΔH/kJmol−1	ΔS/JK−1
A	-25	-80
B	-22	40
C	25	-50
D	22	20

The number of non-spontaneous processes from the following is

The d-electronic configuration of $\left[ CoCl _4\right]^{2-}$ in tetrahedral crystal field is $e ^{ m } t _2 ^n$ Sum of "$m$" and "number of unpaired electrons" is

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).

When $Fe _{0.93} O$ is heated in presence of oxygen, it converts to $Fe _2 O _3$ The number of correct statement/s from the following is
A. The equivalent weight of $Fe _{093} O$ is Molecular wejght $0.79$
B. The number of moles of $Fe ^{2+}$ and $Fe ^{3+}$ in 1 mole of $Fe _{0.93} O$ is $0.79$ and $014$ respectively
C. $Fe _{0.93} O$ is metal deficient with lattice comprising of cubic closed packed arrangement of $O ^{2-}$ ions
D. The $\%$ composition of $Fe ^{2+}$ and $Fe ^{3+}$ in $Fe _{093} O$ is $85 \%$ and $15 \%$ respectively

The dissociation constant of acetic acid is $x \times 10^{-5}$ When $25 \,mL$ of $0.2 \,M \,CH _3 COONa$ solution is mixed with $25 \,mL$ of $0.02\, M \,CH _3 COOH$ solution, the $pH$ of the resultant solution is found to be equal to 5. The value of $x$ is ___