List of top Chemistry Questions asked in JEE Main

Following are the four molecules ``P``, ``Q``, ``R`` and ``S``. Which one among the four molecules will react with H-Br(aq) at the fastest rate? Molecules:

\[ P: \text{Cyclic compound with two O groups attached to the ring.} \] \[ Q: \text{Cyclic compound with one O group and one CH\(_3\) group attached to the ring.} \] \[ R: \text{Cyclic compound with one O group attached to the ring and one CH\(_3\) group attached to the ring.} \] \[ S: \text{Cyclic compound with one CH\(_3\) group attached to the ring.} \]

Which of the following Statements are NOT true about the periodic table? 
A. The properties of elements are a function of atomic weights. 
B. The properties of elements are a function of atomic numbers. 
C. Elements having similar outer electronic configuration are arranged in the same period. 
D. An element's location reflects the quantum numbers of the last filled orbital. 
E. The number of elements in a period is the same as the number of atomic orbitals available in the energy level that is being filled.

Which of the following linear combinations of atomic orbitals will lead to the formation of molecular orbitals in homonuclear diatomic molecules (internuclear axis in z-direction)?
(1) \( 2p_z \) and \( 2p_x \) 
(2) \( 2s \) and \( 2p_x \) 
(3) \( 3d_{xy} \) and \( 3d_{x^2-y^2} \) 
(4) \( 2s \) and \( 2p_z \) 
(5) \( 2p_z \) and \( 3d_{x^2-y^2} \) 
 

For a reaction, \[ {N}_2{O}_5(g) \rightarrow 2{NO}_2(g) + \frac{1}{2} {O}_2(g) \] in a constant volume container, no products were present initially. The final pressure of the system when 50% of the reaction gets completed is:

Which of the following statement is true with respect to H\(_2\)O, NH\(_3\) and CH\(_4\)? 
(A) The central atoms of all the molecules are sp\(^3\) hybridized. 
(B) The H–O–H, H–N–H and H–C–H angles in the above molecules are 104.5°, 107.5° and 109.5° respectively. 
(C) The increasing order of dipole moment is CH\(_4\)<NH\(_3\)<H\(_2\)O. 
(D) Both H\(_2\)O and NH\(_3\) are Lewis acids and CH\(_4\) is a Lewis base. 
(E) A solution of NH\(_3\) in H\(_2\)O is basic. In this solution NH\(_3\) and H\(_2\)O act as Lowry-Bronsted acid and base respectively. 
 

Aman has been asked to synthesise the molecule: 

Using an aldol condensation reaction. He found a few cyclic alkenes in his laboratory.
He thought of performing ozonolysis reaction on the alkene to
produce a dicarbonyl compound followed by aldol reaction to prepare "x".
Predict the suitable alkene that can lead to the formation of "x".

For the given cell: \[ {Fe}^{2+}(aq) + {Ag}^+(aq) \to {Fe}^{3+}(aq) + {Ag}(s) \] The standard cell potential of the above reaction is given. The standard reduction potentials are given as: \[ {Ag}^+ + e^- \to {Ag} \quad E^\circ = x \, {V} \] \[ {Fe}^{2+} + 2e^- \to {Fe} \quad E^\circ = y \, {V} \] \[ {Fe}^{3+} + 3e^- \to {Fe} \quad E^\circ = z \, {V} \] The correct answer is:

The carbohydrates “Ribose” present in DNA is 
A. A pentose sugar 
B. Present in pyranose form 
C. In “D” configuration 
D. A reducing sugar, when free 
E. In \( \alpha \)-anomeric form

Given below are two statements I and II. 
Statement I: Dumas method is used for estimation of "Nitrogen" in an organic compound. 
Statement II: Dumas method involves the formation of ammonium sulfate by heating the organic compound with concentrated H\(_2\)SO\(_4\). In the light of the above statements, choose the correct answer from the options given below: