List of top Chemistry Questions

At \(T\) K, the equilibrium constant for the reaction \[ {H}_2(g) + {Br}_2(g) \rightleftharpoons 2 {HBr}(g) \] is 1.6 \(\times\) 10\(^{1}\). If 10 bar of HBr is introduced into a sealed vessel at \(T\) K, the equilibrium pressure of HBr (in bar) is approximately:

The molar heats of fusion and vaporization of benzene are 10.9 and 31.0 kJ mol\(^{-1}\) respectively. The changes in entropy for the solid \(\rightarrow\) liquid and liquid \(\rightarrow\) vapor transitions for benzene are \(x\) and \(y\) J K\(^{-1}\) mol\(^{-1}\) respectively. The value of \(y(x)\) in J\(^2\) K\(^{-2}\) mol\(^{-2}\) is:

The volume of an ideal gas contracts from 10.0 L to 2.0 L under an applied pressure of 2.0 atm. During contraction, the system also evolved 90 J of heat. The change in internal energy (in J) involved in the system is (1 L·atm = 101.3 J):

What is the kinetic energy (in \( {J/mol} \)) of one mole of an ideal gas (molar mass = \(0.01 \, {kg/mol}\)) if its rms velocity is \(4 \times 10^2 \, {m/s}\)?

What is the ratio of kinetic energies of \(3 \, {g}\) of hydrogen and \(4 \, {g}\) of oxygen at a certain temperature?
Among the following species, the correct set of isomolecular pairs are: \[ \mathrm{XeO}_3, \, \mathrm{CO}_3^{2-}, \, \mathrm{SO}_3, \, \mathrm{H}_3\mathrm{O}^+, \, \mathrm{ClF}_3 \]
Observe the following reactions. Identify the reaction in which the hybridisation of the underlined atom is changed:

Match the following elements with their correct classifications: 

The graph shown below represents the variation of probability density, \( \Psi(r) \), with distance \( r \) of the electron from the nucleus. This represents: 

If uncertainty in position and momentum of an electron are equal, then uncertainty in its velocity is:

If an iron (III) complex with the formula \[\left[ \text{Fe}(\text{NH}_3)_x (\text{CN})_y \right]^-\]has no electron in its \( e_g \) orbital, then the value of \( x + y \) is:
If one strand of a DNA has the sequence ATGCTTCA, sequence of the bases in complementary strand is:
Choose the correct option for free expansion of an ideal gas under adiabatic condition from the following :
Ionic reactions with organic compounds proceed through:
(A) Homolytic bond cleavage
(B) Heterolytic bond cleavage
(C) Free radical formation
(D) Primary free radical
(E) Secondary free radical
Choose the correct answer from the options given below:
Given below are two statements :
Statement (I) : Potassium hydrogen phthalate is a primary standard for standardisation of sodium hydroxide solution.
Statement (II) : In this titration phenolphthalein can be used as indicator.
In the light of the above statements, choose the most appropriate answer from the options given below:
Identify A and B in the following sequence of reaction.
Reaction
In Kjeldahl’s method for estimation of nitrogen, CuSO\(_4\) acts as:
In acidic medium, \( K_2Cr_2O_7 \) shows oxidizing action as represented in the half-reaction: \(Cr_2O_7^{2-} + XH^+ + Ye^- \rightarrow 2A + ZH_2O\)
\( X \), \( Y \), \( Z \), and \( A \) are respectively:
Match List – I with List –II.
Match
Choose the correct answer from options given below:
According to the wave-particle duality of matter by de-Broglie, which of the following graph plot presents most appropriate relationship between wavelength of electron () and momentum of electron (p)?
Given below are two statements:
Statement (I) : The NH2 group in Aniline is ortho and para directing and a powerful activating group.
Statement (II) : Aniline does not undergo Friedel- Craft’s reaction (alkylation and acylation). In the light of the above statements
Choose the most appropriate answer from the options given below :
Given below are two statements:
Statement (I) : Aminobenzene and aniline are same organic compounds.
Statement (II) : Aminobenzene and aniline are different organic compounds.
In the light of the above statements, choose the most appropriate answer from the options given below:
Number of optical isomers possible for 2 – chlorobutane ________
In case of isoelectronic species the size of F– , Ne and Na+ is affected by:
From the given list, the number of compounds with +4 oxidation state of Sulphur_____.
\(SO_3​, H_2​SO_3​, SOCl_2​, SF_4​, BaSO_4​, H_2​S_2​O_7\)​.