List of top Questions asked in CBSE CLASS XII

Write the reactions of D-Glucose with the following:

(a) HI
(b) \(Br_2\) water
(c) Conc. \(HNO_3\)
Write IUPAC names of the following coordination compounds:

(i) \([Ag(NH_3)_2][Ag(CN)_2]\)

(ii) \(K_3[Fe(C_2O_4)_3]\)
Following reaction takes place in one step:

\(2A + B \rightarrow 2C\)

How will the rate of above reaction change if the volume of the reaction vessel is decreased to one third of its original volume? Will there be any change in the order of reaction with the reduced volume?
Differentiate between the following:

(i) Peptide linkage and Glycosidic linkage

(ii) Essential amino acids and Non-essential amino acids
(i) Give a chemical test to show that \([Co(NH_3)_5SO_4]Cl\) and \([Co(NH_3)_5Cl]SO_4\) are ionisation isomers.

(ii) What is meant by the 'Chelate effect'? Give an example.
For the first order thermal decomposition reaction, following data was obtained:

\(C_2H_5Cl(g) \rightarrow C_2H_4(g) + HCl(g)\)

[structure - image pending]

Calculate rate constant.
[Given: log 3 = 0.48]
Assertion (A): The pentaacetate of glucose does not react with \(H_2N-OH\).
Reason (R): It indicates the presence of free −CHO group in glucose.
Why are haloarenes less reactive towards nucleophilic substitution reaction? Give two reasons.
What type of deviation from Raoult's law is shown by a mixture of phenol and aniline? Give reason.
What will happen to the boiling point of the solution on mixing phenol and aniline?
The deficiency of which of the following vitamins causes increased fragility of red blood cells and muscular weakness?
Which of the following amines has lowest \(pK_b\) value?
Assertion (A): The presence of −OH group in phenols directs the incoming group to meta position in the ring.
Reason (R): −OH group in phenols activates the aromatic ring towards electrophilic substitution reaction.
Assertion (A): Actinoids show wide range of oxidation states.
Reason (R): Actinoids are radioactive in nature.
Assertion (A): It is not possible to separate the components of an azeotrope by fractional distillation.
Reason (R): Components of an azeotrope have the same composition in liquid and vapour phase and boil at a constant temperature.
Aniline on direct nitration yields
At low temperature, phenol reacts with dil. \(HNO_3\) to yield
Which of the following is 'not' true about enantiomers?
The secondary valency of Co in the complex \([Co(NH_3)_5(NO_2)]^{2+}\) is
What will happen during the electrolysis of aqueous solution of \(CuCl_2\) by using platinum electrodes?
Which of the following represents the fraction of molecules with energies equal to or greater than \(E_a\)?
Aspirin is obtained by acetylation of
Which of the following curve represents the first order reaction?
Which of the following solutions will have the lowest freezing point in water?
Which of the following is not a transition metal?