List of top Chemistry Questions asked in JEE Main

In good quality cement ratio of lime total oxides of Si(SiO$_2$), Aluminium(Al$_2$O$_3$) and Iron(Fe$_2$O$_3$) should be as close as possible to _____ .

Statement-1: Methyl orange is a weak acid
Statement-2: Benzenoid form of methyl orange is deeply coloured than quinonoid form
Check out which of the above statement is true?

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

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 ______.

When 2 litre of ideal gas expands isothermally into vacuum to a total volume of 6 litre, the change in internal energy is______J (Nearest integer)

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$^{-1}$.

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).

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

[Given : $h=6.626\times10^{-34}Js$

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

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 ]

Some amount of dichloromethane $\left( CH _2 Cl _2\right)$ is added to $671.141 \,mL$ of chloroform $\left( CHCl _3\right)$ to prepare $2.6 \times 10^{-3} M$ solution of $CH _2 Cl _2$ (DCM) The concentration of DCM is ______$ppm$ (by mass) Given: atomic mass : $C =12$ $H =1$ $Cl =35.5$ density of $CHCl _3=1.49\, g \,cm ^{-3}$

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: \[\log 5 = 0.698, \, \log 7 = 0.845, \, \log 2 = 0.301.\]

The number of electrons involved in the reduction of permanganate to manganese dioxide in acidic medium is _______

A $300\, mL$ bottle of soft drink has $0.2 \,M\, CO _2$ dissolved in it Assuming $CO _2$ behaves as an ideal gas, the volume of the dissolved $CO _2$ at STP is ______$mL$ (Nearest integer) Given : At STP, molar volume of an ideal gas is $227\, L \,mol ^{-1}$

A litre of buffer solution contains $01$ mole of each of $NH _3$ and $NH _4 CL$ On the addition of $002$ mole of $HCl$ by dissolving gaseous $HCl$, the $pH$ of the solution is found to be ____ $\times 10^{-3}$ (Nearest integer) [Given : $pK _5\left( NH _3\right)=4745$ $ \log 2=0301$ $\log 3=0477$ $T =298 K ]$

The osmotic pressure of solutions of PVC in cyclohexanone at $300 K$ are plotted on the graph The molar mass of $PVC$ is ____$g \,mol ^{-1}$ (Nearest integer)

( Given : R = 0.083 L atm K^-1 mol^-1 )

For the first order reaction $A \rightarrow B$, the half life is $30 min$ The time taken for $75 \%$ completion of the reaction is min (Nearest integer) Given : $\log _g 2=03010$ $ \log 3=04771 $ $ \log 5=06989$

$Pt(s) ∣ H2(g)(1atm) ∣ H+(aq, [H+]=1)\, ∥\, Fe3+(aq), Fe2+(aq) ∣ Pt(s)$
Given$ E^∘_{Fe^{3+}Fe^{2+}}$$=0.771V$ and $E^∘_{H^{+1/2}H_2}=0\,V,T=298K$
If the potential of the cell is 0.712V, the ratio of concentration of $Fe2+$ to $Fe3+$ is

In sulphur estimation, $0471 \,g$ of an organic compound gave $14439 \,g$ of barium sulphate The percentage of sulphur in the compound is ___(Nearest Integer) (Grven: Atomic mass Ba: $137 \,u , S : 32\, u , O : 16 \,u$ )

How many of the following metal ions have similar value of spin only magnetic moment in gaseous state? (Given: Atomic number: $V, 23; Cr, 24; Fe, 26; Ni, 28$) $V ^{3+} \cdot Ci ^{3+} \cdot Fe ^{2+} \cdot Ni ^{3+}$

The strength of $50$ volume solution of hydrogen peroxide is _____$g / L$ (Nearest integer)
Given: Molar mass of $H _2 O _2$ is $34\, g \, mol ^{-1}$ Molar volume of gas at $STP =22.7\, L$

Lead storage battery contains $38 \%$ by weight solution of $H _2 SO _4$ The van't Hoff factor is $2.67$ at this concentration The temperature in Kelvin at which the solution in the battery will freeze is ______(Nearest integer) Given $K _f=1.8\, K \,kg\, mol ^{-1}$