List of top Questions asked in JEE Main

Number of water molecules in washing soda and soda ash respectively are :

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R:
Assertion A: The energy required to form \(Mg^{2+}\) from Mg is much higher than that required to produce \(Mg^+\)
Reason R: \(Mg^{2+}\) is small ion and carry more charge than \(Mg^{+}\).
In the light of the above statements, choose the correct answer from the options given below.

The correct order of the number of unpaired electrons in the given complexes is
A. \([Fe(CN)_6]^{3–}\)
B. \([FeF_6]^{3–}\)
C. \([CoF_6]^{3–}\)
D. \([Cr(oxalate)_3]^{3–}\)
E. \([Ni(CO)_4]\)
Choose the correct answer from the options given below:

Match List I with List II:

List I - Complex		List II - Crystal Field Splitting energy (△₀)
A.	[Ti(H₂O)₆]²⁺	I.	– 1.2
B.	[V(H₂O)₆]²⁺	II.	– 0.6
C.	[Mn(H₂O)₆]³⁺	III.	0
D.	[Fe(H₂O)₆]³⁺	IV.	– 0.8

Choose the correct answer from the options given below:

The decreasing order of hydride affinity for following carbocations is:

The decreasing order of hydride affinity

Choose the correct answer from the options given below:

The major product P formed in the given reaction is:

The major product P formed

Incorrect method of preparation for alcohols from the following is:

Buna-S can be represented as:

The reaction used for preparation of soap from fat is :

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R:
Assertion A: 3.1500 g of hydrated oxalic acid dissolved in water to make 250.0 mL solution will result in 0.1 M oxalic acid solution.
Reason R: Molar mass of hydrated oxalic acid is 126 g mol^–1.
In the light of the above statements, choose the correct answer from the options given below.

The electron in the \(n^{th}\) orbit of \(Li^{2+}\) is excited to \((n + 1)\) orbit using the radiation of energy \(1.47 × 10^{–1}J \) (as shown in the diagrarn). The value of n is ______ .
Given: \(R_H = 2.18 × 10^{–18} J\).

The number of endothermic process/es from the following is _____ .
A. \(I_2 (g) → 2I (g)\)
B. \(HCl (g) → H(g) + Cl (g)\)
C. \(H_2O(l) → H_2O (g)\)
D. \(C(s) + O_2 (g) → CO_2 (g)\)
E. Dissolution of ammonium chloride in water.

An aqueous solution of volume 300 cm³ contains 0.63 g of protein. The osmotic pressure of the solution
at 300 K is 1.29 mbar. The molar mass of the protein is ____ g mol^–1.
Given: R = 0.083 L bar K^–1 mol^–1

\(A(g) ⇋ 2B(g) + C(g)\)
For the given reaction, if the initial pressure is 450 mm Hg and the pressure at time t is 720 mm Hg at a constant temperature T and constant volume V. The fraction of A(g) decomposed under these conditions is \(x × 10^{–1}\). The value of x is _____ . (nearest integer)

The specific conductance of 0.0025 M acetic acid is \(5 × 10^{–5} S\ cm^{–1}\) at a certain temperature. The dissociation constant of acetic acid is ___________ \(× 10^{–7}.\) (Nearest integer) Consider limiting molar conductivity of \(CH_3COOH\) as \(400\ S cm^2 mol^{–1}\).

The number of incorrect statement/s from the following is ____ .
A. The successive half lives of zero order reactions decreases with time.
B. A substance appearing as reactant in the chemical equation may not affect the rate of reaction.
C. Order and molecularity of a chemical reaction can be a fractional number.
D. The rate constant units of zero and second order reaction are mol L^–1s^–1 and mol^–1 Ls^–1 respectively.

The difference in the oxidation state of \(Xe\) between the oxidised product of \(Xe\) formed on complete hydrolysis of \(XeF_4\) and \(XeF_4\) is _____ .

In alkaline medium, the reduction of permanganate anion involves a gain of _____ electrons.

If \(\begin{vmatrix} x+1 & x & x \\ x & x+ \lambda & x \\ x & x & x+ \lambda^2 \end{vmatrix}\)= \(\frac{9}{8}\) \((103x + 81)\), then \(λ\) and \(\frac{λ}{3}\) are roots of the equation

Let a, b, c and d be positive real numbers such that a + b + c + d = 11. If the maximum value of \(a^5b ^3c ^2d\) is \(3750\;\beta\), then the value of \(\beta\) is

Let A = {1, 3, 4, 6, 9} and B = {2, 4, 5, 8, 10}. Let R be a relation defined on A × B such that R = {(\((a_1, b_1),(a_2, b_2)\)) : \(a_1 ≤ b_2\) and \(b_1 ≤ a_2\)}. Then the number of elements in the set R is

Let P be the plane passing through the points (5, 3, 0), (13, 3, –2) and (1, 6, 2). For α ∈ N, if the distances of the points A (3, 4, α) and B (2, α, a) from the plane P are 2 and 3 respectively, then the positive value of a is

The converse of ((~ p) ∧ q) ⇒ r is

If the radius of the largest circle with centre (2, 0) inscribed in the ellipse \(x^2 + 4y^2 = 36\) is r, then \(12r^2\) is equal to

Let the function f: [0,2] \(\rightarrow\) R be defined as \(f(x) = \begin{cases} e^{min}{x^2,x-[x]} & \quad x \in[0,1]\\ e^{[x-log_ex]} & \quad x\in[1,2] \end{cases}\)
where [t] denotes the greatest integer less than or equal to t. Then the value of the integral \(\int^2_0xf(x)dx\) is