List of top Chemistry Questions asked in JEE Main

The mass of magnesium required to produce 220 mL of hydrogen gas at STP on reaction with excess of dilute HCl is: (Given molar mass of Mg = 24 g/mol)
The purification method based on the following physical transformation is: \[ {Solid} \xrightarrow{{Heat}} {Vapour} \xrightarrow{{Cool}} {Solid} \]

1.24 g of $ {AX}_2 $ (molar mass 124 g mol$^{-1}$) is dissolved in 1 kg of water to form a solution with boiling point of 100.105$^\circ$C, while 2.54 g of $ {AY}_2 $ (molar mass 250 g mol$^{-1}$) in 2 kg of water constitutes a solution with a boiling point of 100.026$^\circ$C. $ K_{b(H_2O)} = 0.52 \, \text{K kg mol}^{-1} $. Which of the following is correct?

Rate law for a reaction between $A$ and $B$ is given by $\mathrm{R}=\mathrm{k}[\mathrm{A}]^{\mathrm{n}}[\mathrm{B}]^{\mathrm{m}}$. If concentration of A is doubled and concentration of B is halved from their initial value, the ratio of new rate of reaction to the initial rate of reaction $\left(\frac{\mathrm{r}_{2}}{\mathrm{r}_{1}}\right)$ is

Niobium (Nb) and ruthenium (Ru) have "x" and "y" number of electrons in their respective 4d orbitals. The value of \( x + y \) is: 
The total number of compounds from below when treated with hot KMnO4 giving benzoic acid is:
hot KMnO4 giving benzoic acid
Only litre buffer solution was prepared by adding 0.10 mol each of $ NH_3 $ and $ NH_4Cl $ in deionised water. The change in pH on addition of 0.05 mol of HCl to the above solution is _____ $ \times 10^{-2} $, (Nearest integer) (Given : $ pK_b $ of $ NH_3 = 4.745 $ and $ \log_{10}3 = 0.477 $)

Total number of nucleophiles from the following is: \(\text{NH}_3, PhSH, (H_3C_2S)_2, H_2C = CH_2, OH−, H_3O+, (CH_3)_2CO, NCH_3\)

Fortification of food with iron is done using $\mathrm{FeSO}_{4} .7 \mathrm{H}_{2} \mathrm{O}$. The mass in grams of the $\mathrm{FeSO}_{4} .7 \mathrm{H}_{2} \mathrm{O}$ required to achieve 12 ppm of iron in 150 kg of wheat is _______ (Nearest integer).} (Given : Molar mass of $\mathrm{Fe}, \mathrm{S}$ and O respectively are 56,32 and $16 \mathrm{~g} \mathrm{~mol}^{-1}$ )

At 715 mm pressure, 300 K, volume of N\(_2\) (g) evolved was 80 mL by a 0.4 g sample of organic compound. Find the percentage of N in the organic compound. Given aqueous tension at 300 K = 15 mm.

Consider the following molecules:
 
The order of rate of hydrolysis is:

Match List - I with List - II. 

List - I (Complex)List - II (Hybridisation)
(A) \([\text{CoF}_6]^{3-}\)(I) \( d^2 sp^3 \)
(B) \([\text{NiCl}_4]^{2-}\)(II) \( sp^3 \)
(C) \([\text{Co(NH}_3)_6]^{3+}\)(III) \( sp^3 d^2 \)
(D) \([\text{Ni(CN}_4]^{2-}\)(IV) \( dsp^2 \)











Choose the correct answer from the options given below:

For $\mathrm{A}_{2}+\mathrm{B}_{2} \rightleftharpoons 2 \mathrm{AB}$ $\mathrm{E}_{\mathrm{a}}$ for forward and backward reaction are 180 and $200 \mathrm{~kJ} \mathrm{~mol}^{-1}$ respectively. If catalyst lowers $\mathrm{E}_{\mathrm{a}}$ for both reaction by $100 \mathrm{~kJ} \mathrm{~mol}^{-1}$. Which of the following statement is correct?

Identify correct conversion during acidic hydrolysis from the following: 
(A) Starch gives galactose. 
(B) Cane sugar gives equal amount of glucose and fructose. 
(C) Milk sugar gives glucose and galactose. 
(D) Amylopectin gives glucose and fructose. 
(E) Amylose gives only glucose. 
Choose the correct answer from the options given below:

Statement 1: Fructose can give Tollens' test even though it does not have an aldehyde group.
Statement 2: When reacted with base, fructose can undergo rearrangement to produce an aldehyde group.

Given below are two statements: 
Statement I: D-(+)-glucose + D-(+)-fructose $\xrightarrow{H_2O}$ sucrose sucrose $\xrightarrow{\text{Hydrolysis}}$ D-(+)-glucose + D-(+)-fructose
Statement II: Invert sugar is formed during sucrose hydrolysis. 
In the light of the above statements, choose the correct answer from the options given below -

Given below are two statements :
Statement (I) : On hydrolysis, oligo peptides give rise to fewer number of $ \alpha $-amino acids while proteins give rise to a large number of $ \beta $-amino acids.
Statement (II) : Natural proteins are denatured by acids which convert the water soluble form of fibrous proteins to their water insoluble form.
In the light of the above statements, choose the most appropriate answer from the options given below :
The species which does not undergo disproportionation reaction is:
Which of the following mixing of 1M base and 1M acid leads to the largest increase in temperature?
The molecules having square pyramidal geometry are:
The molarity of a 70%(mass/mass) aqueous solution of a monobasic acid (X) is:
A compound 'X' absorbs 2 moles of hydrogen and 'X' upon oxidation with KMnO4 - H⁺ gives the following products:
A compound 'X' absorbs 2 moles of hydrogen and 'X' upon oxidation with KMnO4
The total number of \(\sigma\) bonds present in the compound 'X' is ----.
For bacterial growth in a cell culture, growth law is very similar to the law of radioactive decay. Which of the following graphs is most suitable to represent bacterial colony growth? Where \( N \) - Number of Bacteria at any time, \( N_0 \) - Initial number of Bacteria.
Given below are two statements:
Statement (I): On nitration of m-xylene with \( \text{HNO}_3 \), \( \text{H}_2\text{SO}_4 \), followed by oxidation, 4-nitrobenzene-1, 3-dicarboxylic acid is obtained as the major product.
Statement (II): CH\(_3\) group is o/p-directing while NO\(_2\) group is m-directing group.
In the light of the above statements, choose the correct answer from the options given below:
The hydration energies of $ K^+ $ and $ Cl^- $ are $ -x $ and $ -y $ kJ/mol respectively. If lattice energy of KCl is $ -z $ kJ/mol, then the heat of solution of KCl is :