List of top Chemistry Questions asked in CBSE CLASS XII

Rosenmund reduction is used for the preparation of Aldehydes. The catalyst used in this reaction is:
Which of the following acids represents Vitamin C?
From the elements of 3d series below, which element shows the maximum number of oxidation states?
Which alkyl halide from the given options will undergo S$_N$1 reaction faster?
The correct Mathematical expression of Arrhenius equation is:
Aniline readily reacts with bromine water to give 2, 4, 6-tribromoaniline.
Arrange the following compounds in the increasing order of their basic strength in the gaseous phase:
C$_6$H$_5$NH$_2$, (C$_2$H$_5$)$_3$N, (C$_2$H$_5$)$_2$NH
Give reasons for the following:
Methyl amine is more basic than aniline.
Primary amines have higher boiling points than tertiary amines.
A solution containing 2 g of glucose (M = 180 g mol$^{-1}$) in 100 g of water is prepared at 303 K. If the vapour pressure of pure water at 303 K is 32.8 mm Hg, what would be the vapour pressure of the solution?
Define reverse osmosis.
Calculate the mass of CaCl$_2$ (molar mass = 111 g mol$^{-1}$) to be dissolved in 500 g of water to lower its freezing point by 2K, assuming that CaCl$_2$ undergoes complete dissociation.
Why are aquatic species more comfortable in cold water in comparison to warm water?
Define ideal solution.
Predict whether Van’t Hoff factor will be less or greater than one when Ethanoic acid is dissolved in benzene.
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.
What is Hinsberg’s reagent?
Why are transition elements good catalysts?
Why is first ionization enthalpy of chromium lower than that of Zn?
What is Lanthanoid contraction?
Why Zinc is not regarded as a transition element?
What happens when ethyl chloride is treated with alcoholic potassium hydroxide?
Predict whether \([CoF_6]^{3-}\) is diamagnetic or paramagnetic and why?
\([Atomic \ \ number : Co = 27]\)
Show that the time required for 99.9% completion in a first-order reaction is 10 times of half-life (t$_{1/2}$) of the reaction.
Write the IUPAC name of the given compound:
3– Bromo– 1 chlorocyclohexene