List of top Chemistry Questions asked in CBSE CLASS XII

Write the reaction of glucose with:
(a) HI
(b) Br₂ water

The resistance of 0.05 M CH\(_3\)COOH solution is found to be 100 ohm. If the cell constant is 0.0354 cm\(^{-1}\), calculate the molar conductivity of the acetic acid solution.
Write the stepwise mechanism of nucleophilic addition reactions in the carbonyl compounds.
The compound which undergoes SN1 reaction most rapidly is:
Two among the three components of DNA are $\beta$-D-2-deoxyribose and a heterocyclic base. The third component is:
Which one of the following first row transition elements is expected to have the highest third ionization enthalpy?
An amide ‘A’ with molecular formula C$_7$H$_7$ON undergoes Hoffmann Bromamide degradation reaction to give amine ‘B’. ‘B’ on treatment with nitrous acid at 273-278 K forms ‘C’ and on treatment with chloroform and ethanolic potassium hydroxide forms ‘D’. ‘C’ on treatment with ethanol gives ‘E’. Identify ‘A’, ‘B’, ‘C’, ‘D’ and ‘E’ and write the sequence of chemical equations.

If amines are arranged in increasing order of their basic strength in gaseous phase, the correct order will be:

The most stable complex among the following is:

Williamson's synthesis of preparing dimethyl ether is a/an:

Write the reaction involved in:
(a) Reimer-Tiemann reaction
(b) Kolbe's reaction

Give plausible explanation for: 
(a) Diazonium salts of aromatic amines are stable.
(b) Aniline does not undergo Friedel-Crafts reaction. 
(c) Aniline on nitration gives substantial meta product.

The correct IUPAC name of (CH₃)₃C-CH₂Br is:

The IUPAC name of the complex [Co(NH₃)₅(ONO)]Cl₂ is:

Which of the following does not undergo Aldol condensation?

The geometry of paramagnetic nickel complex [NiCl₄]²⁻ is:

Out of Fe²⁺, Co²⁺, Cr³⁺, Ni²⁺, the one which shows the lowest magnetic moment is:
[Atomic number: Fe = 26, Co = 27, Ni = 28, Cr = 24]

For a chemical reaction A → B, the rate doubles when the concentration of A is increased four times. The order of reaction is

Considering the strength of the ligand, the highest excitation energy will be observed in:

The chemical test which can be used to distinguish between ethanamine and aniline is:

How can you obtain potassium dichromate from sodium chromate?
The vapour pressure of a solvent at 283 K is 100 mm Hg. Calculate the vapour pressure of a dilute solution containing 1 mole of a strong electrolyte AB in 50 moles of the solvent at 283 K (assuming complete dissociation of solute AB).
A solution is prepared by dissolving 5 g of a non-volatile solute in 200 g of water. It has a vapor pressure of 31.84 mm Hg at 300 K. Calculate the molar mass of the solute.
(Vapor pressure of pure water at 300 K = 32 mm Hg)
Calculate the potential of Iron electrode in which the concentration of Fe2+ ion is 0.01 M. Given \( E^{\circ}_{\text{Fe}^{2+}/\text{Fe}} = -0.45 \, \text{V at 298 K} \)
[Given: log 10 = 1]
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?