List of top Chemistry Questions asked in JEE Main

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): In expensive scientific instruments, silica gel is kept in watch-glasses or in semipermeable membrane bags.
Reason (R): Silica gel adsorbs moisture from air via adsorption, thus protects the instrument from water corrosion (rusting) and/or prevents malfunctioning.
In the light of the above statements, choose the correct answer from the options given below:

Which of the following compounds would give the following set of qualitative analysis?
• (i) Fehling’s Test: Positive
• (ii) Na fusion extract upon treatment with sodium nitroprusside gives a blood red colour but not

For \(\text{OF}_2\) molecule consider the following:
[(A)] Number of lone pairs on oxygen is 2.
[(B)] F--O--F angle is less than \(104.5^\circ\).
[(C)] Oxidation state of O is \(-2\).
[(D)] Molecule is bent ‘V’-shaped.
[(E)] Molecular geometry is linear.
Correct options are:

To inhibit the growth of tumours, identify the compounds used from the following:
(A) EDTA
(B) Coordination Compounds of Pt
(C) D – Penicillamine
(D) Cis – Platin
Choose the correct answer from the options given below:

What is the correct order of acidity of the protons marked A-D in the given compounds?

Formation of photochemical smog involves the following reaction in which A, B, and C are respectively:
\(\text{NO}_2 \xrightarrow{h\nu} \text{A} + \text{B}\)
\(\text{B} + \text{O}_2 \rightarrow \text{C}\)
\(\text{A} + \text{C} \rightarrow \text{NO}_2 + \text{O}_2\)
Choose the correct answer from the options given below:

The alkaline earth metal sulphate(s) which are readily soluble in water is/are:
(a) BeSO₄
(b) MgSO₄
(c) CaSO₄
(d) SrSO₄
(e) BaSO₄
Choose the correct answer from the options given below:

Consider the following reaction approaching equilibrium at \(27^\circ \text{C}\) and 1 atm pressure:
\[\text{A + B} \rightleftharpoons \text{C + D}\]
\[K_f = 10^3, \quad K_r = 10^2\]
The standard Gibbs energy change (\(\Delta_r G^\circ\)) at \(27^\circ \text{C}\) is — kJ mol\(^{-1}\) (Nearest integer).

Following chromatogram was developed by adsorption of compound 'A' on a 6 cm TLC glass plate. Retardation factor of the compound 'A' is_____ \(\times 10^{–1}\).

Millimoles of calcium hydroxide required to produce 100 mL of the aqueous solution of pH 12 is \(x \times 10^{-1}\). The value of \(x\) is — (Nearest integer).

Water decomposes at 2300 K:
\[2\text{H}_2\text{O}(g) \rightleftharpoons 2\text{H}_2(g) + \text{O}_2(g).\]
The percent of water decomposing at 2300 K and 1 bar is — (Nearest integer).
Equilibrium constant for the reaction is \(2 \times 10^{-3}\) at 2300 K.

Following figure shows dependence of molar conductance of two electrolytes on concentration. Λ^o _m is the limiting molar conductivity. The number of incorrect statement(s) from the following is ________ 

(A) \(\Lambda \text{o m}\) for electrolyte A is obtained by extrapolation. 
(B) For electrolyte B, \(\Lambda \text{m}\) vs \(\sqrt c\) graph is a straight line with intercept equal to o \(\Lambda \text{m}\)
(C) At infinite dilution, the value of degree of dissociation approaches zero for electrolyte B. 
(D) Λo m for any electrolyte A or B can be calculated using \(\lambda0\) for individual ions.

For 1 mol of gas, the plot of pV vs. p is shown below. p is the pressure and V is the volume of the gas. What is the value of compressibility factor at point A?

The increasing order of pKa for the following phenols is 
(A) 2,4-Dinitrophenol 
(B) 4-Nitrophenol 
(C) 2,4,5-Trimethylphenol 
(D) Phenol 
(E) 3-Chlorophenol 
Choose the correct answer from the option given below :

Which of the following salt solutions would coagulate the colloid solution formed when FeCl₃ is added to NaOH solution, at the fastest rate?

Match List I with List II

Choose the correct answer from the option given below: