List of top Chemistry Questions asked in CBSE CLASS XII

The correct Mathematical expression of Arrhenius equation is:
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$1 reaction faster?
Which of the following acids represents Vitamin C?
Rosenmund reduction is used for the preparation of Aldehydes. The catalyst used in this reaction is:
Arrange the following compounds in the increasing order of their basic strength in the gaseous phase:
C$_6$H$_5$NH$_2$, (C$_2$H$_5$)$_3$N, (C$_2$H$_5$)$_2$NH
Give reasons for the following:
Methyl amine is more basic than aniline.
Primary amines have higher boiling points than tertiary amines.
Aniline readily reacts with bromine water to give 2, 4, 6-tribromoaniline.
Predict whether Van’t Hoff factor will be less or greater than one when Ethanoic acid is dissolved in benzene.
A solution containing 2 g of glucose (M = 180 g mol$^{-1}$) in 100 g of water is prepared at 303 K. If the vapour pressure of pure water at 303 K is 32.8 mm Hg, what would be the vapour pressure of the solution?
Define reverse osmosis.
Why are aquatic species more comfortable in cold water in comparison to warm water?
Calculate the mass of CaCl$_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.
Define ideal solution.
What is Hinsberg’s reagent?
Why are transition elements good catalysts?
Why Zinc is not regarded as a transition element?
What is Lanthanoid contraction?
Why is first ionization enthalpy of chromium lower than that of Zn?
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.
What happens when ethyl chloride is treated with alcoholic potassium hydroxide?
Predict whether \([CoF_6]^{3-}\) is diamagnetic or paramagnetic and why?
\([Atomic \ \ number : Co = 27]\)
What is meant by a unidentate ligand? Give an example.
Write chemical equations for the following reactions:
(a) Hydroboration – Oxidation reaction:
(b) Williamson Synthesis:
(c) Friedel-Crafts Alkylation of Anisole:
(d) Reimer-Tiemann Reaction: