List of top Chemistry Questions asked in JEE Main

Given below are two statements:
Statement I : The non bio-degradable fly ash and slag from steel industry used by cement industry.
Statement II : The fuel obtained from plastic waste is lead free.
In the light of the above statements, choose the most appropriate answer from the options given below:
Ka1, Ka2 and Ka3 are the respective ionization constants for the following reactions (a),(b), and (c).
(a) H2C2O4⇌H++HC2O4−
(b) HC2O4−⇌H++HC2O42−
(c) H2C2O4⇌2H++C2O42−
The relationship between Ka1,Ka2 and Ka3 is given as
Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: Phenolphthalein is a pH dependent indicator, remains colourless in acidic solution and gives pink colour in basic medium.
Reason R: Phenolphthalein is a weak acid. It doesn’t dissociate in basic medium.
In the light of the above statements, choose the most appropriate answer from the options given below.
Which of the following enhances the lathering property of soap?

The normality of H2SO4 in the solution obtained on mixing 100 mL of 0.1 M H2SO4 with 50 mL of 0.1 M NaOH is ________ × 10–1 N. (Nearest Integer)

For a real gas at 25°C temperature and high pressure (99 bar) the value of the compressibility factor is 2, so the value of van der Waal’s constant ‘b’ should be ______ × 10–2 L mol–1 (Nearest integer).
(Given R=0.083 L bar K-1 mol-1)
A gas (Molar mass = 280 g mol–1) was burnt in excess O2 in a constant volume calorimeter and during combustion the temperature of calorimeter increased from 298.0 K to 298.45 K. If the heat capacity of calorimeter is 2.5 kJ K–1 and enthalpy of combustion of gas is 9 kJ mol–1 then amount of gas burnt is __________g. (Nearest Integer).
[A] → [B]
Reactant Product
If formation of compound [B] follows the first order of kinetics and after 70 minutes the concentration of [A] was found to be half of its initial concentration. Then the rate constant of the reaction is x × 10–6 s–1. The value of x is _________. (Nearest Integer).
Among the following ores Bauxite, Siderite, Cuprite, Calamine, Haematite, Kaolinite, Malachite, Magnetite, Sphalerite, Limonite, Cryolite, the number of principal ores of iron is____.
The oxidation state of manganese in the product obtained in a reaction of potassium permanganate and hydrogen peroxide in basic medium is____.

The number of molecules(s) or ions(s) from the following having non-planar structure is ____.
\(NO^-_3, H_2O_2, BF_3, PCl_3, XeF_4, SF_4, XeO_3, PH^+_4, SO3,[Al(OH)_4]^-\)

The spin only magnetic moment of the complex present in Fehling’s reagent is_____ B.M. (Nearest integer).
In the given reaction,
\( \begin{array}{l}X+Y+3Z\rightleftharpoons XYZ_3\end{array}\)
if one mole of each of X and Y with 0.05 mol of Z gives compound XYZ3. (Given : Atomic masses of X, Y and Z are 10, 20 and 30 amu, respectively.) the yield of XYZ3 is _______ g. (Nearest integer)

Choose the correct answer :

1. Production of iron in blast furnace follows the following equation

Fe3O4(s)+4CO(g)→3Fe(I)+4CO22(g)

when 4.640 kg of Fe3O4 and 2.520 kg of CO are allowed to react then the amount of iron (in g) produced is

[Given : Molar Atomic mass (g mol–1) : Fe = 56

Molar Atomic mass (g mol–1) : O = 16

Molar Atomic mass (g mol–1) : C = 12]

Given below are two statements : Statement I : On heating with \(KHSO _4\), glycerol is dehydrated and acrolein is formed 
Statement II : Acrolein has fruity odour and can be used to test glycerol's presence Choose the correct option
Two statements in respect of drug-enzyme interaction are given below 
Statement I: Action of an enzyme can be blocked only when an inhibitor blocks the active site of the enzyme. 
Statement II: An inhibitor can form a strong covalent bond with the enzyme. 
In the light of the above statements, choose the correct answer from the options given below
The reaction of zinc with excess of aqueous alkali, evolves hydrogen gas and gives:
Fig.

The stable carbocation formed in the above reaction is

Which of the following conditions or reaction sequence will NOT give acetophenone as the major product?
Which of the following is the correct plot for the probability density ψ2(r) as a function of distance ‘r’ of the electron from the nucleus for 2s orbital?
\(250\) \(g\) solution of \(D-glucose\) in water contains 10.8% of carbon by weight. The molality of the solution is nearest to (Given: Atomic Weights are, \(H, 1 u; C, 12 u; O, 16 u\))

20 mL of 0.02 M hypo solution is used for the titration of 10 mL of copper sulphate solution, in the presence of excess of KI using starch as an indicator. The molarity of \(Cu^{2+}\) is found to be ________ × \(10^{–2} M\). [nearest integer]

Considering the reaction sequence given below, the correct statement(s) is(are)
The oxide which contains an odd electron at the nitrogen atom is
Octahedral complexes of copper(II) undergo structural distortion (Jahn-Teller). Which one of the given copper(II) complexes will show the maximum structural distortion?
(en – ethylenediamine;H2N−CH2−CH2−NH2)