List of top Chemistry Questions asked in CBSE CLASS XII

What is the effect of temperature on the rate of reaction? Write a mathematical expression for the same.
Assertion (A): Henry’s law constant (KH) decreases with increase in temperature.
Reason (R): As the temperature increases, solubility of gases in liquids decreases.
Assertion (A): For measuring resistance of an ionic solution an AC source is used.
Reason (R): Concentration of ionic solution will change if DC source is used.
Which of the following aqueous solutions will have the highest freezing point?
The treatment of ethyl bromide with alcoholic silver nitrite gives:
In which of the following groups are both ions coloured in aqueous solution?
A plot between concentration of reactant [R] and time ‘t’ is shown below. Which of the given order of reaction is indicated by the graph?
concentration of reactant [R] and time
CH3CH2OH can be converted to CH3CHO by :
The IUPAC name for CH3 - CH2 - N(CH3) - CH2 - CH2 - CH3 is :
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)
Write chemical equations for the following reactions:
(a) Hydroboration – Oxidation reaction:
(b) Williamson Synthesis:
(c) Friedel-Crafts Alkylation of Anisole:
(d) Reimer-Tiemann Reaction:
Which of the following compounds will give a ketone on oxidation with chromic anhydride (CrO3})?
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]
What type of deviation is shown by ethanol and acetone mixture ? Give reason. What type of azeotropic mixture is formed by that deviation ?
Which one of the following first row transition elements is expected to have the highest third ionization enthalpy?
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).
What is the structural feature that characterizes a reducing sugar?
How many Faradays are required for the oxidation of one mole of \( \text{H}_2\text{O} \) to \( \text{O}_2 \)?
Write the chemical equation when:
(a) Butan-2-one is treated with Zn(Hg) and conc. HCl.
(b) Two molecules of benzaldehyde are treated with conc. NaOH.
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?
Which of the following alkyl halides will undergo S$_N$1 reaction most readily?
Anisole reacts with HI to give:
Write the stepwise mechanism of nucleophilic addition reactions in the carbonyl compounds.
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 were obtained for the reaction
A 1% solution of solute ‘X’ is isotonic with a 6% solution of sucrose (molar mass = \( 342 \) g mol\(^{-1}\)). The molar mass of solute ‘X’ is: