List of top Chemistry Questions asked in JEE Main

Acidic ferric chloride solution on treatment with excess of potassium ferrocyanide gives a Prussian blue coloured colloidal species. It is:
The kinetic energy of an electron in the second Bohr orbit of a hydrogen atom is equal to \(\frac{h^2}{x m a_0^2}\). The value of \(10x\) is _________. (\(a_0\) is radius of Bohr's orbit)
(Nearest integer)
[ Given : \(\pi = 3.14\) ]
200 mL of 0.2 M HCl is mixed with 300 mL of 0.1 M NaOH. The molar heat of neutralization of this reaction is \(-57.1\) kJ. The increase in temperature in \(^\circ C\) of the system on mixing is \(x \times 10^{-2}\). The value of \(x\) is _________. (Nearest integer)
[ Given : Specific heat of water \(= 4.18 \, \text{J g}^{-1} \text{K}^{-1}\)
Density of water \(= 1.00 \, \text{g cm}^{-3}\) ]
(Assume no volume change on mixing)
1 kg of 0.75 molal aqueous solution of sucrose can be cooled up to \(-4^\circ C\) before freezing. The amount of ice (in g) that will be separated out is _________. (Nearest integer)
[ Given : \(K_f(H_2O) = 1.86 \, \text{K kg mol}^{-1}\) ]
The number of moles of \(NH_3\) that must be added to 2 L of 0.80 M \(AgNO_3\) in order to reduce the concentration of \(Ag^+\) ions to \(5.0 \times 10^{-8}\) M (\(K_{\text{formation}}\) for \([Ag(NH_3)_2]^+ = 1.0 \times 10^8\)) is _________. (Nearest integer)
[ Assume no volume change on adding \(NH_3\) ]
When 10 mL of an aqueous solution of \(KMnO_4\) was titrated in acidic medium, equal volume of 0.1 M of an aqueous solution of ferrous sulphate was required for complete discharge of colour. The strength of \(KMnO_4\) in grams per litre is _________ \(\times 10^{-2}\). (Nearest integer)
[ Atomic mass of \(K = 39, Mn = 55, O = 16\) ]
The reaction that occurs in a breath analyser, a device used to determine the alcohol level in a person's blood stream is:
\(2 K_2Cr_2O_7 + 8 H_2SO_4 + 3 C_2H_6O \to 2 Cr_2(SO_4)_3 + 3 C_2H_4O_2 + 2 K_2SO_4 + 11 H_2O\)
If the rate of appearance of \(Cr_2(SO_4)_3\) is \(2.67 \, \text{mol min}^{-1}\) at a particular time, the rate of disappearance of \(C_2H_6O\) at the same time is _________ \(\text{mol min}^{-1}\). (Nearest integer)
The number of \(f\) electrons in the ground state electronic configuration of Np (\(Z = 93\)) is _________. (Integer answer)
1 mol of an octahedral metal complex with formula $MCl_3 \cdot 2L$ on reaction with excess of $AgNO_3$ gives 1 mol of $AgCl$. The denticity of Ligand L is _________. (Integer answer)
In Carius method for estimation of halogens, 0.2 g of an organic compound gave 0.188 g of $AgBr$. The percentage of bromine in the compound is _________. (Nearest integer)
[Atomic mass : $Ag = 108, Br = 80$]
The number of moles of $CuO$, that will be utilized in Dumas method for estimating nitrogen in a sample of 57.5 g of N,N-dimethylaminopentane is $x \times 10^{-2}$. (Nearest integer)
Lyophilic sols are more stable than lyophobic sols because,
The correct order of ionic radii for the ions, P\(^{3-}\), S\(^{2-}\), Ca\(^{2+}\), K\(^{+}\), Cl\(^{-}\) is:

Choose the most appropriate answer from the options given below : 

Choose the correct statement from the following:
Which one of the following is formed (mainly) when red phosphorus is heated in a sealed tube at 803 K ?
Which one of the following is used to remove most of plutonium from spent nuclear fuel ?
In stratosphere most of the ozone formation is assisted by :
Which one of the following tests used for the identification of functional groups in organic compounds does not use copper reagent ?

The major product of the following reaction, if it occurs by S\(_N\)2 mechanism is : 

 

Which one of the following reactions will not yield propionic acid ?

Which one of the following is the major product of the given reaction ? 

 

Given below are two statements:
Statement I : Ethyl pent-4-yn-oate on reaction with CH\(_3\)MgBr gives a 3\(^\circ\)-alcohol.
Statement II : In this reaction one mole of ethyl pent-4-yn-oate utilizes two moles of CH\(_3\)MgBr.
In the light of the above statements, choose the most appropriate answer from the options given below :

Which one of the following chemicals is responsible for the production of HCl in the stomach leading to irritation and pain ? 

The addition of dilute NaOH to Cr\(^{3+}\) salt solution will give :