List of top Chemistry Questions asked in JEE Main

Number of moles of methane required to produce 22g \(CO_{2​(g)}\) after combustion is \(x × 10^{−2}\) moles. The value of x is

Given below are two statements:
One is labelled as Assertion A and the other is labelled as Reason R: 
Assertion A: \(pK_a\)​ value of phenol is 10.0 while that of ethanol is 15.9. 
Reason R: Ethanol is stronger acid than phenol. 
In the light of the above statements, choose the correct answer from the options given below:

Integrated rate law equation for a first order gas phase reaction is given by (where \(P_i\)​ is initial pressure and \(P_t\)​ is total pressure at time t)

Adsorption' principle is used for which of the following purification method?

The product of the following reaction is P.

The number of hydroxyl groups present in the product P is ______.

The number of species from the following in which the central atom uses sp3 hybrid orbitals in its bonding is ______. \(NH_3​, SO_2​, SiO_2​, BeCl_2​, CO_2​, H_2​O, CH_4​, BF_3\)​

The correct sequence of electron gain enthalpy of the elements listed below is
A. Ar 
B. Br 
C. F 
D. S 
Choose the most appropriate 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: Alcohols react both as nucleophiles and electrophiles. 
Reason R: Alcohols react with active metals such as sodium, potassium and aluminum to yield corresponding alkoxides and liberate hydrogen. 
In the light of the above statements, choose the correct answer from the options given below:

The product (C) in the below mentioned reaction is: \(\text{CH}_3 - \text{CH}_2 - \text{CH}_2 - \text{Br} \xrightarrow{\text{KOH}_{(alc)} \Delta} A \xrightarrow{\text{HBr}} B \xrightarrow{\text{KOH}_{(alc)}\Delta} C\)
 

The total number of hydrogen atoms in product A and product B is ______.

Number of alkanes obtained on electrolysis of a mixture of \(CH_3​COONa\) and \(C_2​H_5​COONa\) is___.

Identify the factor from the following that does not affect electrolytic conductance of a solution.

A species having carbon with sextet of electrons and can act as electrophile is called

Consider the following reaction at 298 K.
\(\frac{3}{2}​O_{2(g)}​⇌O_{3(g)}​,K_p​=2.47×10^{−29}\). 
\(Δ_r​G^{\theta}\) for the reaction is ______ kJ. (Given R=\(8.314\;J K^{−1}mol^{−1}\))

The ionization energy of sodium in \(kJ \;mol^{−1}\). If electromagnetic radiation of wavelength 242 nm is just sufficient to ionize sodium atom is ______.

The compound that is white in color is

Identify the mixture that shows positive deviations from Raoult's Law

For the given reaction, choose the correct expression of \(K_c\)​ from the following: \(Fe_{(aq)}^{3+}​+SCN_{(aq)}^{−}​⇌(FeSCN)_{(aq)}^{2+}\)​

Give below are two statements:
Statement-I : Noble gases have very high boiling points. 
Statement-II: Noble gases are monoatomic gases. They are held together by strong dispersion forces. Because of this they are liquefied at very low temperature. Hence, they have very high boiling points. 
In the light of the above statements, choose the correct answer from the options given below.

The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency \( 'A' \times 10^{12} \, \text{hertz} \) and that has a radiant intensity in that direction of \( \frac{1}{'B'} \, \text{watt per steradian} \). 'A' and 'B' are respectively:

Consider the following first-order gas phase reaction at constant temperature \[ \text{A(g)} \rightarrow 2\text{B(g)} + \text{C(g)} \] If the total pressure of the gases is found to be 200 torr after 23 sec. and 300 torr upon the complete decomposition of \( \text{A} \) after a very long time, then the rate constant of the given reaction is \( \dots \dots \times 10^{-2} \, \text{s}^{-1} \) (nearest integer). \[ \text{[Given: } \log_{10}(2) = 0.301 \text{]} \]

When \( \Delta H_{\text{vap}} = 30 \, \text{kJ/mol} \) and \( \Delta S_{\text{vap}} = 75 \, \text{J mol}^{-1} \text{K}^{-1} \), then the temperature of vapour, at one atmosphere, is \( \dots \dots \dots \, \text{K} \).

One Faraday of electricity liberates \(x×10^{−1 }\)gram atom of copper from copper sulphate, x is ______.