List of top Questions asked in CBSE CLASS XII- 2026

The correct IUPAC name of the complex $[Pt(NH_3)_2Cl_2]$ is:
Which of the following is heteroleptic complex?
Identify the correct increasing order of boiling points of the given compounds:
Propan-1-ol, butan-1-ol, butan-2-ol, pentan-1-ol
Consider the following reaction:
$Zn_{(s)} + Ag_2O_{(s)} + H_2O_{(l)} \rightarrow Zn^{2+}_{(aq)} + 2Ag_{(s)} + 2OH^-_{(aq)}$
Given: $E^\circ_{Ag^+/Ag} = 0.80~V$, $E^\circ_{Zn^{2+}/Zn} = -0.76~V$, $1~F = 96500~C~mol^{-1}$. $\Delta_r G^\circ$ for the above reaction is:
Electronic configuration of chromium is:
The order for the given reaction is:
$A + 2B \rightarrow Products$
$Rate = k[A]^{\frac{1}{2}}[B]^1$
Identify the correct statement:
The conductivity of $0.1$ mol $L^{-1}$ solution of NaCl is $1.06 \times 10^{-2}$ S $cm^{-1}$. Calculate its molar conductivity and degree of dissociation. ($\lambda^\circ_{Na^+} = 50.1, \lambda^\circ_{Cl^-} = 76.5$ S $cm^2$ $mol^{-1}$). (b) (i) Predict current flow direction for $2Ag^+ + Zn \rightarrow 2Ag + Zn^{2+}$. (ii) Differentiate between primary and secondary battery.
Which phenomenon is responsible for desalination of sea water?
An organic compound ‘A’, with molecular formula $C_2H_6O$ reacts with active metals such as sodium to give compound ‘B’ and hydrogen gas. ‘A’ on treatment with iodine and sodium hydroxide gives ‘C’ and in presence of $H_2SO_4$ at $413$ K gives ‘D’ ($C_4H_{10}O$). ‘D’ on reaction with excess of HI gives ‘E’. Identify ‘A’, ‘B’, ‘C’, ‘D’ and ‘E’ and write all the reactions involved.
How will you convert:
(i) Propanone to Propene,
(ii) Benzoic acid to Benzaldehyde,
(iii) Benzene to m-Nitroacetophenone?
\([\mathrm{Fe(H_2O)_6}]^{2+}\) is paramagnetic whereas \([\mathrm{Fe(CO)_5}]\) is diamagnetic. Justify the statement. [Atomic number of Fe = 26]
On the basis of crystal field theory write the electronic configuration for \( d^4 \) ion if \( \Delta_0 \lt P \).
A solution containing \( 8.0 \text{ g} \) of a non-volatile solute in \( 100 \text{ g} \) of diethyl ether boils at \( 36.86 ^\circ\text{C} \) whereas pure diethyl ether boils at \( 35.60 ^\circ\text{C} \). Determine the molar mass of the solute. (\( K_b \) for diethyl ether = \( 2.02 \text{ K kg mol}^{-1} \))
Explain why actinoid contraction is greater from element to element than lanthanoid contraction.
Rate constant \(k\) for the first order reaction is \( 2.54 \times 10^{-3} \text{ s}^{-1} \). Calculate the time required for three-fourth of the reactant to decompose. (Given: \( \log 4 = 0.60 \))
Calculate emf of the following cell at 298 K :
\( \text{Sn} \mid \text{Sn}^{2+} (0.001 \text{ M}) \parallel \text{H}^+ (0.01 \text{ M}) \mid \text{H}_{2(g)} (1 \text{ bar}) \mid \text{Pt}_{(s)} \)
Given : \( E^\circ_{\text{Sn}^{2+}/\text{Sn}} = - 0.14 \text{ V}, \quad E^\circ_{\text{H}^+/\text{H}_2} = 0.00 \text{ V} \quad [\log 10 = 1] \)
Complete and balance the following equations :
(i) \( 4\text{FeCr}_2\text{O}_4 + 8\text{Na}_2\text{CO}_3 + 7\text{O}_2 \longrightarrow \)
(ii) \( 5\text{Fe}^{2+} + \text{MnO}_4^- + 8\text{H}^+ \longrightarrow \)
Assertion (A) : The molecularity of the given reaction is 2.
\( 2\text{HI} \longrightarrow \text{H}_2 + \text{I}_2 \)
Reason (R) : Two molecules of the reactants are involved in simultaneous collision between them.
The concentration of the reactant is reduced from \( 0.6 \text{ mol L}^{-1} \) to \( 0.2 \text{ mol L}^{-1} \) in \( 5 \text{ minutes} \) in a first order reaction. Calculate rate constant of the reaction. (Given: \( \log 3 = 0.48 \))
Assertion (A) : Aromatic primary amines can be prepared by Gabriel Phthalimide synthesis.
Reason (R) : Aryl halides do not undergo nucleophilic substitution with the anion formed by phthalimide.
Assertion (A) : Zinc, cadmium and mercury are not considered as transition elements.
Reason (R) : These elements have completely filled d-orbitals in their ground state as well as in their common oxidation states.
Identify the correct statement :
Assertion (A) : Glucose gets oxidized to six carbon gluconic acid on reaction with bromine water.
Reason (R) : The carbonyl group is absent in the open chain structure of glucose.
Consider the following reaction :
\( \text{Zn}_{(s)} + \text{Ag}_2\text{O}_{(s)} + \text{H}_2\text{O}_{(l)} \rightarrow \text{Zn}^{2+}_{(aq)} + 2\text{Ag}_{(s)} + 2\text{OH}^-_{(aq)} \)
Given : \( E^\circ_{\text{Ag}^+/\text{Ag}} = 0.80 \, \text{V} \), \( E^\circ_{\text{Zn}^{2+}/\text{Zn}} = -0.76 \, \text{V} \), \( 1 \, \text{F} = 96500 \, \text{C mol}^{-1} \).
\( \Delta_r G^\circ \) for the above reaction is :