List of top Chemistry Questions asked in CBSE CLASS XII

Write IUPAC names of the following coordination entities:
(a)[Fe(en)2Cl2]+
(b)[Co(NH3)4(H2O)Br]SO4
(c)[Ni(CN)4]²−
A solution containing 15 g urea (molar mass = 60 g mol\(^{-1}\)) per litre of solution in water has the same osmotic pressure (isotonic) as a solution of glucose (molar mass = 180 g mol\(^{-1}\)) in water. Calculate the mass of glucose present in one litre of its solution.
Arrange the following compounds in increasing order of their reactivity towards \( S_N2 \) displacement: 2-Bromo-2-methylbutane, 1-Bromopentane, 2-Bromopentane.
In the following pair of halogen compounds, which compound undergoes \( S_N1 \) reaction faster and why?
compound undergoes SN1 reaction faster
When \( \text{FeCr}_2\text{O}_4 \) is fused with \( \text{Na}_2\text{CO}_3 \) in the presence of air, it gives a yellow solution of compound (A). Compound (A) on acidification gives compound (B). Compound (B) on reaction with KCl forms an orange-colored compound (C). An acidified solution of compound (C) oxidizes \( \text{Na}_2\text{SO}_3 \) to (D). Identify (A), (B), (C), and (D).
A reaction is of second order with respect to a reactant. How is the rate of reaction affected if the concentration of the reactant is (i) doubled, (ii) reduced to half?
The rate constant for a zero-order reaction \( A \to P \) is 0.0030 mol L\(^{-1}\) s\(^{-1}\). How long will it take for the initial concentration of A to fall from 0.10 M to 0.075 M?
The charge required for the reduction of 1 mol of \( MnO_4^- \) to \( MnO_2 \) is
The diamagnetic species is :
At. No. Co = 27, Fe =26, Ni= 28]
The element having \([Ar]3d^{10}4s^1\) electronic configuration is
The number of molecules that react with each other in an elementary reaction is a measure of the:
The complex ions \([Co(NH_3)_5(NO_2)]^{2+\) and \([Co(NH_3)_5(ONO)]^{2+}\) are called}
Which is the correct IUPAC name for
1-Chloro-4-Methylbenzene
Which among the following is a false statement?
Assertion (A): In a first order reaction, if the concentration of the reactant is doubled, its half-life is also doubled. Reason (R): The half-life of a reaction does not depend upon the initial concentration of the reactant in a first order reaction.
What will be formed after oxidation of secondary alcohol with chromic anhydride (CrO3)?
Scurvy is caused due to deficiency of
Nucleotides are joined together by
Which of the following is/are examples of denaturation of protein?
The conversion of phenol to salicylic acid can be accomplished by
Assertion (A): Aromatic primary amines cannot be prepared by Gabriel Phthalimide synthesis. Reason (R): Aryl halides do not undergo nucleophilic substitution reaction with the anion formed by phthalimide.
Assertion (A): Vitamin D cannot be stored in our body. Reason (R): Vitamin D is fat-soluble vitamin and is not excreted from the body in urine.
The elements of 3d transition series are given as: Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn
Answer the following:
Read the passage carefully and answer the questions that follow.
Passage: The rate of a chemical reaction is expressed either in terms of decrease in the concentration of reactants or increase in the concentration of a product per unit time. Rate of the reaction depends upon the nature of reactants, concentration of reactants, temperature, presence of catalyst, surface area of the reactants and presence of light. Rate of reaction is directly related to the concentration of reactant. Rate law states that the rate of reaction depends upon the concentration terms on which the rate of reaction actually depends, as observed experimentally. The sum of powers of the concentration of the reactants in the Rate law expression is called order of reaction while the number of reacting species taking part in an elementary reaction which must collide simultaneously in order to bring about a chemical reaction is called molecularity of the reaction.
 Answer the following questions:
Phenols undergo electrophilic substitution reactions readily due to the strong activating effect of the OH group attached to the benzene ring. Since the OH group increases the electron density more to the ortho- and para- positions, one of the examples of the aldehyde group being introduced on the aromatic ring of phenol, ortho to the hydroxyl group. This is a general method used for the ortho-formylation of phenols.
Answer the following questions: