List of top Chemistry Questions asked in CBSE CLASS XII

Why are equimolar solutions of sodium chloride and glucose not isotonic?
Define colligative property. Which colligative property is preferred for the molar mass determination of macromolecules?
The vapour pressures of A and B at 25°C are 75 mm Hg and 25 mm Hg, respectively. If A and B are mixed such that the mole fraction of A in the mixture is 0.4, then calculate the mole fraction of B in the vapour phase.
1 molal aqueous solution of an electrolyte \( A_2B_3 \) is 60% ionized. Calculate the boiling point of the solution.
How does the size of blood cells change when placed in an aqueous solution containing more than 0.9% (mass/volume) sodium chloride?
At the same temperature, \( CO_2 \) gas is more soluble in water than \( O_2 \) gas. Which one of them will have a higher value of \( K_H \) and why?
Complete and balance the following chemical equations: 
Thermal decomposition of Potassium Permanganate
\( E^0 \) value of Cu\(^{2+}\)/Cu is \( +0.34 \) V.
Of the \( d^4 \) species, Cr\(^{2+}\) is strongly reducing while Mn\(^{3+}\) is strongly oxidizing.
Account for the following : The melting and boiling points of Zn, Cd, and Hg are low.
The following initial rate data were obtained for the reaction: \[ 2\text{NO (g)} + \text{Br}_2 \text{(g)} \rightarrow 2 \text{NOBr (g)} \] initial rate data
Which isomer of C4H9Cl has the lowest boiling point?
Out of chlorobenzene and 2,4,6-trinitrochlorobenzene, which is more reactive towards nucleophilic substitution and why?
Identify the type of isomerism exhibited by the following complexes:
(i) [Co(NH3)5NO2]2+
(ii) [Co(en)3]3+Cl3
Arrange the following complexes in the increasing order of conductivity of their solution: \[ [\text{Cr(NH}_3\text{)}_5\text{Cl}] \text{Cl}_2, \, [\text{Cr(NH}_3\text{)}_3\text{Cl}_3], \, [\text{Cr(NH}_3\text{)}_6\text{Cl}_3] \]
Write the formula for the following coordination compound: Potassium tetrahydroxidozincate (II)
Write the main product in each of the following reactions: 
oxidation of the hydroboration product
Write the mechanism of the following reaction: \[ \text{CH}_3\text{CH}_2\text{OH} \xrightarrow{H^+ \, 443\, \text{K}} \text{CH}_2 = \text{CH}_2 \]
What is peptide linkage?
Write two differences between order of reaction and molecularity of reaction.
Write the chemical equations when: Pentan-3-one is treated with H$_2$N–NH$_2$ followed by heating with KOH in high boiling solvent such as ethylene glycol.
Draw the structures of major monohalo products in each of the following reactions:
monohalo products
Assertion (A): Transition metals have high enthalpy of atomization. Reason (R): This is because transition metals have low melting points.
Assertion (A): The pK$_a$ of O$_2$N–CH$_2$–COOH is lower than that of CH$_3$–COOH. Reason (R): The –NO$_2$ group shows an electron-withdrawing effect, which increases the acidic character of O$_2$N–CH$_2$–COOH.
The IUPAC name of CH$_3$–C(=O)–CH$_2$–C(=O)–H is: