List of top Questions asked in CBSE CLASS XII

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 charge required for the reduction of 1 mol of \( MnO_4^- \) to \( MnO_2 \) is
Arrange the following compounds in increasing order of their reactivity towards \( S_N2 \) displacement: 2-Bromo-2-methylbutane, 1-Bromopentane, 2-Bromopentane.
The number of molecules that react with each other in an elementary reaction is a measure of the:
Which among the following is a false statement?
Which is the correct IUPAC name for
1-Chloro-4-Methylbenzene
The diamagnetic species is :
At. No. Co = 27, Fe =26, Ni= 28]
The element having \([Ar]3d^{10}4s^1\) electronic configuration is
The complex ions \([Co(NH_3)_5(NO_2)]^{2+\) and \([Co(NH_3)_5(ONO)]^{2+}\) are called}
Assertion (A): Cu cannot liberate \( H_2 \) on reaction with dilute mineral acids. Reason (R): Cu has positive electrode potential.
Nucleotides are joined together by
Scurvy is caused due to deficiency of
Which of the following is/are examples of denaturation of protein?
What will be formed after oxidation of secondary alcohol with chromic anhydride (CrO3)?
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.
The conversion of phenol to salicylic acid can be accomplished by
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.
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.
An alkene A with molecular formula C\(_6\)H\(_{10}\) on ozonolysis gives a mixture of two compounds B and C. Compound B gives positive Fehling test and also reacts with iodine and NaOH solution. Compound C does not give Fehling solution test but forms iodoform. Identify the compounds A, B, and C.
Using \( E^\circ \) values of X and Y given below, predict which is better for coating the surface of iron to prevent corrosion and why?
Given: \( E^\circ_{X^{2+}/X} = -2.36 \, \text{V} \) \( E^\circ_{Y^{2+}/Y} = -0.14 \, \text{V} \) \( E^\circ_{Fe^{2+}/Fe} = -0.44 \, \text{V} \)
Define Azeotrope. What type of Azeotrope is formed by negative deviation from Raoult's law? Give an example.
The correct IUPAC name of [Pt(NH$_3$)$_2$Cl$_2$]$^{2+} $ is:
The magnetic moment is associated with its spin angular momentum and orbital angular momentum. Spin only magnetic moment value of Cr$^{3+}$ ion (Atomic no. : Cr = 24) is:
Standard electrode potential for Sn$^{4+}$/Sn$^{2+}$ couple is +0.15 V and that for the Cr$^{3+}$/Cr couple is -0.74 V. The two couples in their standard states are connected to make a cell. The cell potential will be:
The elements of 3d transition series are given as: Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn
Answer the following: