List of top Chemistry Questions asked in JEE Main

The energy of one mole of photons of radiation of frequency 2 \(\times\)10¹² H_z in Jmol^-1 is ________ (Nearest integer) 

[Given : \(h=6.626\times10^{-34}Js\)

 \(N_{A}=6.022\times10^{23}mol^{-1}\)]

Zinc reacts with hydrochloric acid to give hydrogen and zinc chloride The volume of hydrogen gas produced at STP from the reaction of $115 \, g$ of zine with excess $HCl$ is ___$L$ (Nearest integer)
(Given: Molar mass of $Zn$ is $654 \,g \,mol ^{-1}$ and Molar volume of $H _2$ at $STP =227 \,L$ )

The number of alkali metal(s), from Li, K, Cs, $Rb$ having ionization enthalpy greater than $400\, kJ$ $mol ^{-1}$ and forming stable super oxide is

On complete combustion, $0.492\, g$ of an organic compound gave $0.792 \,g$ of $CO _2$ The $\%$ of carbon in the organic compound is(Nearest integer)

A sample of a metal oxide has formula $M _{0.83} O _{1.00}$ The metal $M$ can exist in two oxidation states $+2$ and $+3$ In the sample of $M _{0.83} O _{1.00}$, the percentage of metal ions existing in $+2$ oxidation state is___$ \%$ (nearest integer)

A trisubstituted compound ‘A’, \(\text{C}_{10}\text{H}_{12}\text{O}_2\), gives neutral FeCl\(_3\) test positive. Treatment of compound ‘A’ with NaOH and CH\(_3\)Br gives \(\text{C}_{11}\text{H}_{14}\text{O}_2\), with hydroiodic acid gives methyl iodide, and with hot conc. NaOH gives a compound ‘B’, \(\text{C}_{10}\text{H}_{10}\text{O}_2\). Compound ‘A’ also decolourises alkaline KMnO\(_4\). The number of \(\pi\)-bond/s present in the compound ‘A’ is ______.

The logarithm of equilibrium constant for the reaction $Pd ^{2+}+4 Cl ^{-} \rightleftharpoons PdCl _4^{2-}$ is (Nearest integer) Given : $\frac{230RT }{ F }=006 V$ $Pd _{\text {(aq) }}^{2+}+2 e ^{-} \rightleftharpoons Pd ( s ) \quad E ^{\ominus}=083 V$ $PdCl _4^{2-} \text { (aq) }+2 e ^{-} \rightleftharpoons Pd ( s )+4 Cl ^{-} \text {(aq) } E ^{\ominus}=065 V$

Consider the cell:
\[\text{Pt(s)}|\text{H}_2(g, 1\,\text{atm})|\text{H}^+(aq, 1\,\text{M})||\text{Fe}^{3+}(aq), \text{Fe}^{2+}(aq)||\text{Pt(s)}.\]
When the potential of the cell is 0.712 V at 298 K, the ratio \([\text{Fe}^{2+}]/[\text{Fe}^{3+}]\) is ____ (Nearest integer).

Enthalpies of formation of $CCl _4( g ), H _2 O ( g ), CO _2( g )$ and $HCl ( g )$ are $-105,-242,-394$ and $-92\, kJ$ mol $^{-1}$ respectively The magnitude of enthalpy of the reaction given below is ___$kJ \, mol ^{-1}$ (nearest integer) $CCl _4( g )+2 H _2 O ( g ) \rightarrow CO _2( g )+4 HCl ( g )$

The resistivity of a $0.8 M$ solution of an electrolyte is $5 \times 10^{-3} \Omega cm$ Its molar conductivity is ____ $\times 10^4\, \Omega^{-1}\, cm ^2 \,mol ^{-1}$

The enthalpy change for the conversion of \(\frac{1}{2} Cl_2(g)\) to \(Cl^{-}(aq)\) is (-)_____________ \(KJ mol^{-1}\) (Nearest integer)
Given : \(\Delta_{\text {dis }} H _{ Cl _{2( g )}}^{\ominus}=240\, kJ \,mol ^{-1}\), \(\Delta_{ eg } H _{ Cl }^{\ominus}=-350\, kJ \,mol ^{-1}\), \(\Delta_{\text {hyd }} H ^\theta Cl _{( g )}^{-}=-380 \,kJ \,mol ^{-1}\)

How many of the transformations given below would result in aromatic amines?

Amongst the following, the number of species having the linear shape is $XeF _2, I _3^{+}, C _3 O _2, I _3^{-}, CO _2, SO _2, BeCl _2 \text { and } BCl _2^{\ominus}$

The number of molecules which gives haloform test among the following molecules is

A solution containing 2 g of a non-volatile solute in 20 g of water boils at 373.52 K. The molecular mass of the solute is ------- g mol\(^{-1}\) (Nearest integer).
Given: Water boils at 373 K, \(K_b\) for water = 0.52 K kg mol\(^{-1}\).

The total pressure of a mixture of non-reacting gases $X (0.6 \,g )$ and $Y (0.45 \, g )$ in a vessel is $740 mm$ of $Hg$ The partial pressure of the gas $X$ is ____$mm$ of $Hg$(Nearest Integer)(Given : molar mass $X =20$ and $Y =45 \, g \, mol ^{-1}$ )

At $27^{\circ} C$, a solution containing $25 \,g$ of solute in $2500 \,mL$ of solution exerts an osmotic pressure of $400 \,Pa$. The molar mass of the solute is ____ $g\,mol ^{-1}$. (Nearest integer)
(Given : $R =0.083 \,L\,bar\, K ^{-1} \,mol ^{-1}$ )

The rate constant for a first order reaction is $20 \min ^{-1}$ The time required for the initial concentration of the reactant to reduce to its $\frac{1}{32}$ level is ___$\times 10^{-2} \min$ (Nearest integer) 
(Given: $\ln 10=2.303$ $\log 2=0.3010$ )

If compound A reacts with B following first-order kinetics with rate constant \(2.011 \times 10^{-3} \, \text{s}^{-1}\), the time taken by A (in seconds) to reduce from 7 g to 2 g will be ------- (Nearest Integer).
Given: \[\log 5 = 0.698, \, \log 7 = 0.845, \, \log 2 = 0.301.\]

Assume carbon burns according to following equation : 
$2 C _{( s )}+ O _{2( g )} \rightarrow 2 CO ( g )$ 
When $12 g$ carbon is burnt in $48 g$ of oxygen, the volume of carbon monoxide produced is___ $\times 10^{-1} L$ at STP. [nearest integer]
[Given : Assume $CO$ as ideal gas, Mass of $C$ is $12\, g \,mol ^{-1}$, Mass of $O$ is $16 \,g \,mol ^{-1}$ and molar volume of an ideal gas at STP is $22.7\, L\, mol ^{-1}$ ]

600 mL of 0.01M HCl is mixed with 400 mL of 0.01 M H₂SO₄ .The pH of the mixture is ______ × 10^-2 (Nearest integer) 
[Given log 2 =0.30 , log 3 =0.48 log 5 =0.69  log 7 -0.84 log 11 =1.04 ]

At $298\, K$, the solubility of silver chloride in water is $1434 \times 10^{-3} \,g\, L ^{-1}$. The value of $-\log K _{sp}$ for silver chloride is ____.
(Given: Mass of $Ag$ is $1079\, g\, mol ^{-1}$and mass of $Cl$ is $355 \,g \,mol ^{-1}$ )

Which one of the following statements is incorrect?