List of top Chemistry Questions asked in JEE Main

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R)
Assertion (A): $\alpha$-halocarboxylic acid on reaction with dil $NH _3$ gives good yield of $\alpha$-aminocarboxylic acid whereas the yield of amines is very low when prepared from alkyl halides
Reason (R): Amino acids exist in zwitter ion form in aqueous medium
In the light of the above statements, choose the correct answer from the options given below :

In figure, a straight line is given for Freundrich Adsorption$(y=3 x+2505)$ The value of $\frac{1}{ n }$and$\log K$are respectively

$O - O$ bond length in $H _2 O _2$ is X than the $O - O$ bond length in $F _2 O _2$The $O - H$ bond length in $H _2 O _2$is Y than that of the$O - F$ bond in $F _2 O _2$Choose the correct option for $\underline{X} and \underline{Y}$ from those given below :

When $Cu ^{2+}$ ion is treated with $KI$, a white precipitate, $X$ appears in solution The solution is titrated with sodium thiosulphate, the compound $Y$ is formed $X$ and $Y$ respectively are

Identify $X , Y$ and $Z$ in the following reaction (Equation not balanced) $ClO + NO _2 \rightarrow \underline{ X } \stackrel{ H _2 O }{\longrightarrow} \underline{ Y }+\underline{Z}$

Adding surfactants in non polar solvent, the micelles structure will look like

The methods NOT involved in concentration of ore are
A Liquation
B Leaching
C Electrolysis
D Hydraulic washing
E Froth floatation
Choose the correct answer from the options given below :

A protein ' $X$ ' with molecular weight of $70,000 u$, on hydrolysis gives amino acids One of these amino acid is

In Dumas method for the estimation of $N _2$, the sample is heated with copper oxide and the gas evolved is passed over :

When a hydrocarbon A undergoes complete combustion it requires 11 equivalents of oxygen and produces 4 equivalents of water. What is the molecular formula of $A$?

Arrange the following orbitals in decreasing order of energy
A. $n=3, l =0, m =0$
B. $n =4, l =0, m =0$
C. $n =3, l =1, m =0$
D. $n =3, l =2, m =1$
The correct option for the order is :

Which of the following compounds are not used as disinfectants?
A. Chloroxylenol
B. Bithional
C. Veronal
D. Prontosil
E. Terpineol
Choose the correct answer from the options given below:

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R)
Assertion (A): The first ionization enthalpy of $3d$ series elements is more than that of group 2 metals
Reason (R): In $3d$ series of elements successive filling of d-orbitals takes place
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	Physisorption	i	Single Layer Adsorption
B	Chemisorption	ii	20−40kJmol−1
C	N₂(g)+3H₂(g)—⇢^Fe(s)_^—⇢2NH₃(g)	iii	Chromatography
D	Analytical Application or Adsorption	iv	Heterogeneous catalysis

Choose the correct answer from the options given below:

Evaluate the following statements for their correctness
A. The elevation in boiling point temperature of water will be same for $01 \,M \,NaCl$ and $01\, M$ urea
B. Azeotropic mixtures boil without change in their composition
C. Osmosis always takes place from hypertonic to hypotonic solution
D. The density of $32 \% H _2 SO _4$ solution having molarity $409\, M$ is approximately $126\, g mL ^{-1}$
E. A negatively charged sol is obtained when KI solution is added to silver nitrate solution
Choose the correct answer from the options given below :

Given below are two statements :
Statement I : Upon heating a borax bead dipped in cupric sulphate in a luminous flame, the colour of the bead becomes green.
Statement II : The green colour observerd is due to the formation of copper(I) metaborate.
In the light of the above statements, choose the most appropriate answer from the options given below :

Compound $A , C _5 H _{10} O _5$, given a tetraacetate with $AC _2 O$ and oxidation of $A$ with $Br _2- H _2 O$ gives an acid, $C _5 H _{10} O _6$ Reduction of $A$ with $HI$ gives isopentane The possible structure of $A$ is:

Given below are two statements:
Statement I : H₂O₂ is used in the synthesis of Cephalosporin
Statement II : H₂O₂ is used for the restoration of aerobic conditions to sewage wastes.
In the light of the above statements, choose the most appropriate answer from the options given below :

Which of the following elements have half-filled f-orbitals in their ground state?
(Given : atomic number $Sm =62 ; Eu =63 ; Tb =65 ; Gd =64, Pm =61$ )
A. $Sm$
B. $Eu$
C. $Tb$
D. $Gd$
E. $Pm$
Choose the correct answer from the options given below :

The Lewis acid character of boron tri halides follows the order :

The normal rain water is slightly acidic and its $pH$ value is $56$ because of which one of the following ?

Which one of the following statements is incorrect?

The element playing significant role in neuromuscular function and interneuronal transmission is :

For $OF _2$ molecule consider the following : A Number of lone pairs on oxygen is 2 B FOF angle is less than $1045^{\circ}$ C Oxidation state of $O$ is $-2$ D Molecule is bent ' $V$ ' shaped E Molecular geometry is linear correct options are:

Lithium aluminium hydride can be prepared from the reaction of