CBSE Class 12 Chemistry Paper 1 Sample 2023
Chemistry is full of hidden patterns — and this paper teaches you to spot them in exam time. You'll encounter 15 questions spanning electrochemistry (cells, redox reactions), chemical kinetics (rate laws, activation energy), and transition metals (d-block chemistry, coordination compounds). The mix includes multiple-choice scenarios, true/false concept checks, and fill-in-the-blank definitions — exactly the format you'll see on exam day. This is ideal for Class 12 students revising for the board exam or anyone consolidating mid-year understanding of inorganic reaction mechanisms and thermodynamics. By the end, you'll be able to predict electrode reactions, write rate equations, and identify coordination geometry in seconds.
Questions in this quiz
Answers hidden — play to find out.
- Question 1
A galvanic cell is constructed with a Zn electrode immersed in 1 M ZnSO₄ and a Cu electrode in 1 M CuSO₄, connected by a salt bridge. Under standard conditions, what is the cell potential (E°cell)? (Use E°(Zn²⁺/Zn) = −0.76 V, E°(Cu²⁺/Cu) = +0.34 V)
- Question 2
For a galvanic cell, which statement is true? The cell potential is positive, the reaction is spontaneous, and the anode is the site of oxidation.
- Question 3
Using the Nernst equation, the relationship between cell potential and concentration is E = E° − (0.0592/n) log Q at 25°C. What does Q represent?
- Question 4
A reaction is observed to follow second-order kinetics with respect to reactant A. If the concentration of A is doubled, by what factor does the initial reaction rate increase?
- Question 5
The half-life of a first-order reaction is independent of the initial concentration of the reactant.
- Question 6
A reaction has an activation energy (Eₐ) of 50 kJ/mol and a rate constant k₁ at temperature T₁. Using the Arrhenius equation, if the temperature is increased such that the rate constant becomes k₂ = 4k₁, and R = 8.314 J/(mol·K), approximately by how many Kelvin should the temperature be raised? (Assume Eₐ remains constant)
- Question 7
Which of the following d-block elements typically exhibits the widest range of oxidation states in its compounds?
- Question 8
In the coordination complex [Fe(CN)₆]³⁻, the oxidation state of iron is
- Question 9
Ligands like H₂O and NH₃ are classified as monodentate ligands because they have only one donor atom. Which of the following is a bidentate ligand?
- Question 10
In an octahedral coordination complex, the splitting of d orbitals by the ligand field is such that the dz² and dx²−y² orbitals (eg set) are higher in energy than the dxy, dxz, and dyz orbitals (t2g set). The magnitude of this splitting is called the crystal field splitting energy (Δ) or CFSE.
- Question 11
The complex [CoCl(NH₃)₅]²⁺ exhibits cis–trans (geometric) isomerism. Which isomer has the Cl⁻ and one NH₃ ligand on the same face of the octahedron?
- Question 12
The enthalpy of a redox reaction can be related to the standard cell potential using ΔG = −nFE°, where n is the number of electrons transferred, F is Faraday's constant, and E° is the standard cell potential. At equilibrium, ΔG = 0, so E° =
- Question 13
A reaction with order 2 in A and order 1 in B has a rate law of the form: rate = k[A]ⁿ[B]ᵐ. What is the value of n + m?
- Question 14
Which transition metal element below forms the most stable complexes with carbon monoxide (CO) as a ligand, due to strong backbonding?
- Question 15
In the context of coordination chemistry, a strong field ligand creates a _______ crystal field splitting energy (Δ), favoring the formation of _______ spin complexes.