List of top Chemistry Questions asked in JEE Main

Number of isomeric compounds with molecular formula \(C _9 H _{10} O\) which 
(i) do not dissolve in \(NaOH\)
(ii) do not dissolve in \(HCl\)
(iii) do not give orange precipitate with 2,4-DNP 
(iv) on hydrogenation give identical compound with molecular formula \(C _9 H _{12} O\) is _________
$A$ and $B$ are two substances undergoing radioactive decay in a container The half life of $A$ is $15 min$ and that of $B$ is $5\, min$ If the initial concentration of $B$ is $4$ times that of $A$ and they both start decaying at the same time, how much time will it take for the concentration of both of them to be same? ______ min
The density of \(3 M\) solution of \(NaCl\) is \(10 \,g \,mL -1\). Molality of the solution is _______ \(\times 10^{-2} m\) (Nearest integer). Given: Molar mass of Na and \(Cl\) is \(23\) and \(355 \,g \,mol ^{-1}\) respectively.
Identify the incorrect option from the following:
Match List I with List II 
List IList II
ATranquilizersiAnti blood clotting
BAspiriniiSalvarsan
CAntibioticiiiAntidepressant drugs
DAntisepticivSoframicine

 Choose the correct answer from the options given below:

The correct representation in six-membered pyranose form for the following sugar $ [X]$ is 

But-2-yne is reacted separately with one mole of Hydrogen as shown below: 

 

A. A is more soluble than B
B. B The boiling point & melting point of $A$ are higher and lower than $B$ respectively 
C. A is more polar than $B$ because dipole moment of $A$ is zero 
D. $Br _2$ adds easily to $B$ than $A$ 
Identify the incorrect statements from the options given below:

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 _____________ .
The number of possible isomeric products formed when 3-chioro-1-butene reacts with HCl through carbocation formation is __________
The volume of hydrogen liberated at STP by treating 2.4 g of magnesium with excess of hydrochloric acid is _________ × 10–2 L
Given : Molar volume of gas is 22.4 L at STP.
Molar mass of magnesium is 24 g mol–1
The number of correct statement from the following is _________ .
A. For 1s orbital, the probability density is maximum at the nucleus
B. For 2s orbital, the probability density first increases to maximum and then decreases sharply to zero.
C. Boundary surface diagram of the orbitals encloses a region of 100% probability of finding the electron.
D. p and d-orbitals have 1 and 2 angular nodes respectively E. probability density of p-orbital is zero at the nucleus
Number of compounds from the following which will not produce orange red precipitate with Benedict solution is ____________
Glucose, maltose, sucrose, ribose, 2-deoxyribose, amylose, lactose
The number of correct statements about modern adsorption theory of heterogeneous catalysis from the following is _______
A. The catalyst is diffused over the surface of reactants.
B. Reactants are adsorbed on the surface of the catalyst.
C. Occurrence of chemical reaction on the catalysts surface through formation of an intermediate.
D. It is a combination of intermediate compound formation theory and the old adsorption theory
E. It explains the action of the catalyst as well as those of catalytic promoters and poisons.
The number of correct statements from the following is ______
A. Ecell is an intensive parameter
B. A negative Eθ means that the redox couple is a stronger reducing agent than the H– H2 couple.
C. The amount of electricity required for oxidation or reduction depends on the stoichiometry of the electrode reaction.
D. The amount of chemical reaction which occurs at any electrode during electrolysis by a current is proportional to the quantity of electricity passed through the electrolyte.
The maximum number of lone pairs of electron on the central atom from the following species is ___________
ClO3– , XeF4, SF4 and I3–
The total number of intensive properties from the following is __________
Volume. Molar heat capacity, Molarity, Eθ cell. Gibbs free energy change. Molar mass, Mole
Mg(NO3)2. XH2O and Ba(NO3)2.YH2O, represent formula of the crystalline forms of nitrate salts. Sum of X and Y is _____________ .
Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: [CoCl(NH3)]2– absorbs at lower wavelength of light with respect to [Co(NH3)5(H2O) 3–
Reason R: It is because the wavelength of the light absorbed depends on the oxidation state of the metal ion.
In the light of the above statements, choose the correct answer from the options given below:
Compound ‘B’ is
Compound ‘B’ is
What weight of glucose must be dissolved in 100 g of water to lower the vapour pressure by 0.20 mm Hg?
(Assume dilute solution is being formed)
Given : Vapour pressure of pure water is 54.2 mm Hg at room temperature. Molar mass of glucose is 180 g mol–1 .
Given below arc two statements:
Statement I : In the metallurgy process. sulphide ore is converted to oxide before reduction.
Statement II : Oxide ores in general are easier to reduce.
In the light of the above statements, choose the most appropriate answer from the options given below
Which one of the following pairs is an example of polar molecular solids ?
The major product formed in the following reaction is
 The major product formed in the following reaction is
A. The major product formed in the following reaction is
B.The major product formed in the following reaction is
C.The major product formed in the following reaction is
D.The major product formed in the following reaction is
Choose the correct answer from the options given below:
Match List I with List II
LIST I
Complex		LIST II
Colour
A.Mg(NH4)PO4I.brown
B.K3[Co(NO2)6]II.white
C.MnO(OH)2III.yellow
D.Fe4[Fe(CN)6]3IV.blue

Choose the correct answer from the options given below:
If Ni2– is replaced by Pt2– in the complex NiCl2Br2] 2– , which of the following properties are expected to get changed?
A. Geometry
B. Geometrical isomerism
C. Optical isomerism
D. Magnetic properties