List of top Chemistry Questions asked in JEE Main

The correct order of bond orders of \(C_2^{2-}, N_2^{2-}, O_2^{2-}\) is, respectively

Given below are two statements.
Statement I: The compound

(A) is optically active.
Statement II:

is a mirror image of the above compound A.
In the light of the above statement, choose the most appropriate answer from the options given below.

For complete combustion of methanol
\( CH_3OH(I)+\frac 32O_2(g)→CO_2(g)+2H_2O(I)\)
the amount of heat produced as measured by bomb calorimeter is \(726\) kJ mol^–1 at \(27°C\). The enthalpy of combustion for the reaction is \(x \ kJ mol^{–1}\), where \(x\) is ______ . (Nearest integer)
(Given: \(R= 8.3 \ JK^{–1}mol^{–1}\))

In metallurgy the term “gangue” is used for :

If O₂ gas is bubbled through water at 303 K, the number of millimoles of O₂ gas that dissolve in 1 litre of water is_______. (Nearest integer)
(Given : Henry’s Law constant for O₂ at 303 K is 46.82 k bar and partial pressure of O₂ = 0.920 bar)
(Assume solubility of O₂ in water is too small, nearly negligible)

A sugar ‘X’ dehydrates very slowly under acidic conditions to give furfural which on further reaction with resorcinol gives the coloured product after some time. Sugar ‘X’ is

For the below given cyclic hemiacetal (X), the correct pyranose structure is :

Match List-I with List-I

Choose the correct answer from the option given below:

Among the following marked proton of which compound shows lowest  \(pK_a\) value ?

A protein ‘A’ contains 0.30% of glycine (molecular weight 75). The minimum molar mass of the protein ‘A’ is _______ × 10³ g mol^–1 [nearest integer]

A compound ‘X’ is a weak acid and it exhibits colour change at pH close to the equivalence point during neutralization of NaOH with CH₃COOH. Compound ‘X’ exists in ionized from in basic medium. The compound ‘X’ is

When ethanol is heated with conc. H₂SO₄, a gas is produced. The compound formed, when this gas is treated with cold dilute aqueous solution of Baeyer’s reagent, is

Portland cement contains ‘X’ to enhance the setting time. What is ‘X’?

Consider the following sulphur based oxoacids.
\(H_2SO_3,H_2SO_4,H_2S_2O_8 \)and \(H_2S_2O_7\)
Amongst these oxoacids, the number of those with peroxo (O–O) bonds is_____.

Which of the following 3d-metal ion will give the lowest enthalpy of hydration (Δ_hydH) when dissolved in water?

200 mL of 0.01 M HCl is mixed with 400 mL of 0.01 M H₂SO₄. The pH of the mixture is ___.
[Given log 2 = 0.30, log 3 = 0. 48, log 5 = 0.70, log7 = 0.84, log 11 = 1.04.]

The Hinsberg reagent is

Given below are two statements.
Statement-I: Stannane is an example of a molecular hydride.
Statement-II: Stannane is a planar molecule
In the light of the above statement, choose the most appropriate answer from the options given below.

Dinitrogen is a robust compound, but reacts at high altitudes to form oxides. The oxide of nitrogen that can damage plant leaves and retard photosyn-thesis is

When borax is heated with CoO on a platinum loop, blue coloured bead formed is largely due to

Given below are two statements. One is labelled as Assertion A and the other is labelled as Reason R.
Assertion A : Amylose is insoluble in water.
Reason R : Amylose is a long linear molecule with more than 200 glucose units.
In the light of the above statements, choose the correct answer from the options given below.

The number of chlorine atoms in bithionol is ______ .

1.80 g of solute A was dissolved in 62.5 cm³ of ethanol and freezing point of the solution was found to be 155.1 K. The molar mass of solute A is ____ g mol^–1.
[Given : Freezing point of ethanol is 156.0 K, Density of ethanol is 0.80 g cm^–3, Freezing point depression constant of ethanol is 2.00 K kg mol^–1]