List of top Chemistry Questions asked in JEE Main

\({(1) \,N_2(g) +3H_2(g)<=> 2NH_3(g), K_1}\)
\({(2) \,N_2(g) +O_2(g)<=> 2NHO(g), K_2}\) 
\({(3) \,H_2(g) +\frac{1}{2}O_2(g)<=> H_2O(g), K_3}\) 
The equation for the equilibrium constant of the reaction 
\({2NH_3(g) +\frac{5}{2}O_2(g)<=> 2NO(g), 3H_2O(g)}\), \((K_4)\) in terms of \(K_1\) and \(K_3\) is:

The first ionisation potential of $Na$ is $5.1\, eV$. The value of electron gain enthalpy of $Na^+$ will be

In which of the following pairs of molecules/ions both the species are not likely to exist?

Which of the following represents the correct order of increasing first ionisation enthalpy for $Ca, Ba, S, Se$ and $Ar$?

For gaseous state, if most probable speed is denoted by $c *$, average speed by $\overline{C}$ and root square speed by $c$, then for a large number of molecules, the ratios of these speeds are

Given, $E^\circ _{Cr ^{3+}/Cr} =-0.74\, V;E^\circ_{MnO^-_4/Mn^{2+}}=1.51\, V$ $\, \, \, \, \, E^\circ _{Cr_2 O ^{2-}_7/Cr^{3+}} =-1.33\, V;E^\circ_{Cl/Cl^-}=1.36\, V$ Based on the data given above strongest oxidising agent will be

Which one of the following molecules is expected to exhibit diamagnetic behaviour?

The rate of a reaction doubles when its temperature changes from $300\, K$ to $310\,K$. Activation energy of such a reaction will be $(R = 8.314 JK^{-1} \,mol^{-1}$ and $log \,2 = 0.301)$

Four successive members of the first row transition elements listed below with atomic numbers. Which one of them is expected to have the highest $E_{m{^{3+}}/m{^{2+}}}^{\circ}$value?

Consider the following reaction, $xMnO_4^- + yC_2O_4^{2-}+zH^+ \rightarrow xMn^{2+}+2yCO_2 + \frac{z}{2}H_2O$ The values of x, y and z in the reaction are, respectively

Which of the following arrangements does not represent the correct order of the property stated against it?

\(12\, g\) of a nonvolatile solute dissolved in \(108\, g\) of water produces the relative lowering of vapor pressure of \(0.1.\)The molecular mass of the solute is :

A compound with molecular mass $180$ is acylated with $CH_3COCl$ to get a compound with molecular mass $390$. The number of amino groups present per molecule of the former compound is

A major component of Borsch reagent is obtained by reacting hydrazine hydrate with which of the following ?

A solution of $(-) 1-chloro-1-$phenylethane in toluene racemises slowly in the presence of a small amount of $SbCl_5$, due to the formation of

The order of increasing sizes of atomic radii among the elements $O, S, Se$ and $As$ is :

An ether (A), $C_5H_{12}O$, when heated with excess of hot concentrated $HI$ produced two alkyl halides which when treated with $NaOH$ yielded compounds (B) and (C). Oxidation of (B) and (C) gave a propanone and an ethanoic acid respectively. The IUPAC name of the ether (A) is :

Arrange the following compounds in the order of decreasing acidity

Arrange in the correct order of stability (decreasing order) for the following molecules :

Compound $( A ), C_8H_9Br$ gives a white precipitate when warmed with alcoholic $AgNO_3$. Oxidation of $(A)$ gives an acid $(B)$, $C_8H_6O$ 4. $(B)$ easily forms anhydride on heating. Identify the compound $(A)$.

Calcination is the process in which:

Bond distance in $HF$ is $9.17 \times 10^{-11}\, m$. Dipole moment of $HF$ is $6.10^4 \times 10^{-30}\, Cm$ . The percentage ionic character in $HF$ will be : (electron charge $= 1.60 \times 10^{-19}\, C$)

Electron gain enthalpy with negative sign of fluorine is less than that of chlorine due to :

Equimolar solutions of the following compounds are prepared separately in water. Which will have the lowest pH value ?

Experimentally it was found that a metal oxide has formula $ M_{0.98}O. $ Metal $M$, present as $ M^{2+} $ and $ M^{3+} $ in its oxide.Fraction of the metal which exists as $ M^{3+} $ would be