List of top Chemistry Questions asked in JEE Main

For aA + bB $\rightarrow$ cC + dD, the plot of log k vs 1/T is given below :

The temperature at which the rate constant is $10^{-4}$ s$^{-1}$ is __________ K. [Rate constant is $10^{-5}$ s$^{-1}$ at 500 K.]

The ionization enthalpy of Na$^+$ formation is 495.8, electron gain enthalpy of Br is -325.0, and lattice enthalpy of NaBr is -728.4 kJ mol$^{-1}$. The energy for the formation of NaBr ionic solid is (-) __________ $\times 10^{-1}$ kJ mol$^{-1}$.
Among the following, the number of halide(s) which is/are inert to hydrolysis is ___________: (A) BF$_3$, (B) SiCl$_4$, (C) PCl$_5$, (D) SF$_6$
Consider the reaction: CH$\equiv$CH $\xrightarrow{\text{Red hot Fe}}$ (1) $\xrightarrow{CO, HCl, AlCl_3}$ (2). The number of sp$^2$ hybridized carbon atom(s) in the product is __________.

Using the provided information in paper chromatography

The calculated $R_f$ value of A is __________ $\times 10^{-1}$.

Which of the following are isostructural pairs ? (Note: Based on typical JEE pairs like $SO_4^{2-}$ and $BF_4^-$ or $NH_3$ and $PH_3$)

In Freundlich adsorption isotherm, slope of AB line is : 

Consider the elements Mg, Al, S, P and Si, the correct increasing order of their first ionization enthalpy is :
Which of the following ore is concentrated using group 1 cyanide salt ?

(A) \( \mathrm{HOCl + H_2O_2 \rightarrow H_3O^+ + Cl^- + O_2} \)  |  
(B) \( \mathrm{I_2 + H_2O_2 + 2OH^- \rightarrow 2I^- + 2H_2O + O_2} \). 
Choose the correct option. 

\( \mathrm{Al_2O_3} \) was leached with alkali to get \( X \). The solution of \( X \), on passing the gas \( Y \), forms \( Z \). \( X, Y \) and \( Z \) respectively are :
The electrode potential of \( \mathrm{M^{2+}/M} \) of 3d-series elements shows positive value for :
The major components in “Gun Metal” are :
The gas released during anaerobic degradation of vegetation may lead to :

Which of the following compound gives pink colour on reaction with phthalic anhydride in conc. \( \mathrm{H_2SO_4} \) followed by treatment with \( \mathrm{NaOH} \) ? 

What is the major product formed by HI reaction with

Which of the following reagent is used for the following reaction ? $CH_3CH_2CH_3 \to CH_3CH_2CHO$

The product formed in the first step of the reaction of $CH_3 - CH_2 - CH(Br) - CH_2 - CH(Br) - CH_3$ with excess $Mg/Et_2O$ is :

What is the final product (major) 'A' in the given reaction ? $CH_3 - CH = CH - CH_3 \xrightarrow{HCl} A$ 

Identify products A and B. $CH_3 - CH(CH_3) - CH_3 \xrightarrow{\text{dil. } KMnO_4, 273 K} A \xrightarrow{CrO_3} B$ 

In the following reaction the reason why meta-nitro product also formed is : 

'A' and 'B' in the following reactions ($C_6H_5NH_2 \xrightarrow{CHCl_3/KOH} A \xrightarrow{H_2O/H^+} B$) are : 

Match List I with List II.
List I: (a) Caprolactum (b) 2-Chloro-1,3-butadiene (c) Isoprene (d) Acrylonitrile.
List II: (i) Natural rubber (ii) Buna-N (iii) Nylon 6 (iv) Neoprene.
Out of the following, which type of interaction is responsible for the stabilisation of α-helix structure of proteins ?
Statement I : Colourless cupric metaborate is reduced to cuprous metaborate in a luminous flame. Statement II : Cuprous metaborate is obtained by heating boric anhydride and copper sulphate in a non-luminous flame.