List of top Chemistry Questions asked in CBSE CLASS XII

The two strands in DNA are not identical but complementary. Explain. What products would be formed when DNA is hydrolyzed?
How can you obtain the following?
(a) Aniline from ammonium benzoate
(b) Benzene diazonium chloride from nitrobenzene
(c) 2,4,6-Tribromoaniline from aniline
Why are haloarenes less reactive towards nucleophilic substitution reactions? How does the presence of nitro (–NO₂) group at ortho- and para-positions in haloarenes increase the reactivity towards nucleophilic substitution reactions?
Write the IUPAC name of the complex \([ \text{Pt(en)}_2 \text{Cl}_2 ]^{2+}\). Draw the structure of the geometrical isomer of this complex which is optically inactive.
State a condition under which a bimolecular reaction is kinetically first-order reaction. Give an example. For which type of reactions, do order and molecularity have the same value?
Write the formula of the following coordination compound: Pentaamminecarbonatocobalt(III) chloride.
What is meant by positive deviation from Raoult's law? Give an example. What type of azeotrope is formed by positive deviation?
Write the IUPAC name of the linkage isomer of the complex \([ \text{Co(NH}_3\text{)}_5 \text{(NO}_2\text{)} ]\text{Cl}_2\).
Assertion (A): Vitamin K can be stored in our body.
Reason (R): Vitamin K is a water soluble vitamin.
$\alpha$-helix structure refers to:
Assertion (A): A mixture of o-nitrophenol and p-nitrophenol can be separated by steam distillation.
Reason (R): o-nitrophenol is steam volatile due to intermolecular hydrogen bonding.
Assertion (A): Actinoids show irregularities in their electronic configurations.
Reason (R): Actinoids are radioactive in nature.
Assertion (A): Cooking time is reduced in pressure cooker.
Reason (R): Boiling point of water inside the pressure cooker is elevated.
An amine 'X' reacts with Hinsberg reagent and the product obtained is soluble in alkali. The amine 'X' is:
When alkyl iodide is treated with large excess of ammonia, the major product obtained is:
Which of the following represents the fraction of molecules with energies equal to or greater than E$_a$?
The reaction $R$ -OH + Na $\longrightarrow$ RO$^-$ Na$^+$ + $\frac{1}{2}$ H$_2$ (g) suggests that alcohols are:
The number of moles of AgCl precipitated when excess AgNO$_3$ solution is mixed with one mole of [Co(NH$_3$)$_6$]Cl$_3$ is:
Which of the following haloalkanes react with aqueous KOH most rapidly by $S_N1$ reaction?
At low temperature, phenol reacts with Br$_2$ in CS$_2$ to form:
The activation energy (E$_a$) of a reaction can be determined from the slope of which of the following plots?
Which of the following transition metal ion is not coloured?
During electrolysis of dilute H$_2$SO$_4$ using platinum electrodes, the gas evolved at the anode is:
Which of the following solutions will have the highest boiling point in water?

In the given reaction sequence, the structure of Y would be: