How many questions are there in the ISC Class 12 Chemistry exam paper 2024-25?

As per the available ISC Class 12 Chemistry Specimen Paper 2025, a total of 21 questions are asked in the ISC Class 12 Chemistry exam paper.

The Chemistry question paper of the ISC Class 12 Chemistry is divided into how many sections?

The ISC Class 12 Chemistry question paper is divided into 4 sections: A, B, C, and D.

What is the weightage of every question in the C section of the ISC Class 12 Chemistry paper 2025?

The weightage of every question in the C section of the ISC Class 12 Chemistry Paper 2025 is 3 marks.

ISC Class 12 Chemistry Specimen Paper 2024-25, Solved PDF Download

Table of Contents

The Council of the Indian School Certificate Examinations (CISCE) releases the ISC Class 12 Chemistry Specimen Paper every year for practice. The Chemistry Specimen Paper 2024-25 has been released on the official website of the CISCE. Along with the Chemistry Specimen Paper, the Specimen papers for other subjects have also been released by the Council for the ISC Class 12 Board exam.

The Chemistry subject is an important part of the Science stream of class 12th of the CISCE board. The Specimen Paper is an important reference material that helps students understand the exam pattern and the type of questions that can be asked on the actual exam day. Solving the Specimen paper is very important to score good marks in the board exam.

ISC Class 12 Chemistry Specimen Paper 2024-25

The ISC Class 12 Chemistry Specimen Paper 2024-25 is made available for download at cisce.org. For the convenience of students, we have provided the direct link to download the Chemistry Specimen Paper 2024-25 PDF in the subsequent section. Students must therefore prepare ISC Class 12 Chemistry Specimen Paper in order to achieve good marks on the ISC Class 12 board exam. After doing extensive research, subject matter specialists create the ISC Chemistry Specimen Paper for students.

These Specimen papers are made in accordance with the most recent exam pattern and cover the whole ISC Class 12 Chemistry Syllabus. The Chemistry Class 12 ISC Specimen Paper will definitely help students become more confident. Therefore, it is recommended that students practice them before taking the ISC 12th board exam that is going to be held in February-March 2025.

ISC Chemistry Class 12 Specimen Paper 2025

The most effective tool for assessing students’ performance prior to the board exam is the ISC Specimen Paper for Class 12 Chemistry. The ISC Chemistry class 12 exam specimen paper help students in understanding the level of questions that may be asked in the exam. It also help students understand the weightage of each and every chapter. This specifications of the ISC Class 12 Chemistry exam paper as per the Specimen paper details is given below.

Maximum Marks: 70 Marks

Time Limit of the Exam: 3 hours

Time allocated for Reading the Paper: Additional 15 Minutes

Number of Sections: 4

Sections Name: A, B, C, and D

Section A Marks: 14 Marks

Section B Marks: 20 Marks

Section C Marks: 21 Marks

Section D Marks: 15 Marks

ISC Chemistry Class 12 Specimen Paper 2024-25 Instructions

The Chemistry Specimen Paper 2025 consist of many important instructions that are crucial to know before the exam. Some important details mentioned in the instructions section of the ISC Chemistry Class 12 Specimen Paper 2024-25 is given below.

This paper is divided into four sections – A, B, C and D.
Answer all questions.
Section – A consists of one question having sub-parts of one mark each.
Section – B consists of ten questions of two marks each.
Section – C consists of seven questions of three marks each, and
Section – D consists of three questions of five marks each.
Internal choices have been provided in one question each in Section B, Section C and Section D.
All working, including rough work, should be done on the same sheet as, and adjacent to the rest of the answer.
The intended marks for questions or parts of questions are given in brackets [ ].
Balanced equations must be given wherever possible and diagrams where they are helpful.
When solving numerical problems, all essential working must be shown.

ISC Class 12 Chemistry Specimen Paper 2025 Solved PDF Download

The PDF of the ISC Class 12 Chemistry Specimen Paper is given below. Candidates must go through the Specimen Paper provided below and practice the questions provided in them. This will help students in getting more marks in the exam.

Download ISC Class 12 Chemistry Specimen Paper 2025 PDF

Benefits of ISC Class 12 Chemistry Specimen Paper 2024-25

Students can learn all the key concepts given in the textbook, including the structure of the atom, states of matter, environmental chemistry, chemical thermodynamics, and several p-block elements, by practicing the ISC Class 12 Specimen paper 2024-25 for Chemistry.

Students can effectively prepare for the final exam with the aid of the ISC Class 12 Specimen Paper. The specimen paper allow students to assess their degree of preparedness. In addition to this, completing the specimen paper gives students a greater understanding of the question paper’s design and mark distribution.

ISC Class 12 Chemistry Specimen Paper Previous Year

Students preparing for the chemistry board exam paper in 2025 should also solve the previous year specimen questions along with the questions from the latest specimen paper. Check the previous year questions below.

Section A – 14 Marks

Question 1

(A) Fill in the blanks by choosing the appropriate word(s) from those given in the brackets: [4×1]
[ decreases, CNion, activation energy, catalyst, two, Fe2+ ion, carbon, lattice energy, enzyme, five, double, halogen, triple, increases]

(i) In the Haber process, iron changes the _______ of reaction while molybdenum increases the efficiency of the _________.

(ii) The number of ions that will be produced when potassium ferrocyanide, K4[Fe(CN)6], dissolves in water is _________. This shows that __________ is the ligand in the coordination compound.

(iii) Haloalkenes undergo both nucleophilic and electrophilic reactions due to the presence of __________bond and the __________ atom.

(iv) In case of alcohols, as the carbon chain length increases, the boiling point ____________ and the solubility in water____________.

(B) Select and write the correct alternative from the choices given below: [7×1]

(i) A potassium iodide (KI) solution containing starch turns blue on the addition of chlorine. Which one of the following statements explain this?
(P) The reduction potential of Cl2 is more than that of I2.
(Q) The oxidation potential of Cl2 is more than that of I2.
(R) The product formed when Cl2 combines with starch is blue.
(S) The product formed when I2 combines with starch is blue.

(a) Only P and R
(b) Only Q and R
(c) Only Q and S
(d) Only P and S

(ii) Crystal field splitting energy (CFSE) for high spin d4 octahedral complex is:

(a) -1·6 ∆o
(b) -1·2 ∆o
(c) -0·8 ∆o
(d) -0·6 ∆o

(iii) Acidified K2Cr2O7 solution turns green when Na2SO3 is added to it. This is due to formation of:

(a) CrO42-
(b) Cr2(SO3)3
(c) Cr2O3
(d) Cr2(SO4)3

(iv) Which of the following product is formed when benzene diazonium chloride is reduced by hypophosphorous acid (H3PO2) in the presence of cuprous ion as catalyst?

(a) Phenol

(b) Aniline

(d) Benzene cyanide

(v) Which of the following aqueous solution has lowest vapour pressure?

(a) 1M NaCl
(b) 1M K2SO4
(c) 1M Glucose
(d) 1M Sucrose

(vi) Assertion: Adding water to two beakers ‘A’ and ‘B’ containing NaOH and CH3COOH solutions respectively will increase the molar conductance (ꓥm) of the solutions sharply in beaker ‘A’ and slowly in beaker ‘B’.
Reason: Molar conductance (ꓥm) increases with a decrease in concentration or upon dilution.

(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are true but Reason is not the correct explanation for Assertion.
(c) Assertion is true but Reason is false.
(d) Assertion is false but Reason is true.

(vii) Assertion: Aniline is soluble in HCl while it is only slightly soluble in water.
Reason: Aniline cannot make hydrogen bonds with water but gets protonated easily by acids.

During the winter season in a particular year, Kashmir experienced heavy snowfall. It was an unexpected snowfall. Thousands of visitors were stranded because it was dangerous to travel on snowy roads and vehicles could not move
as water froze in the car radiators. In such conditions officials decided to sprinkle rock salt or CaCl2 on roads.

(i) Why was it decided to sprinkle rock salt or CaCl2 on the roads?
(ii) A mixture of ethylene glycol and water is used as coolant in car radiators. Why?
(iii) How many grams of ethylene glycol (mol. wt. = 62 g mol-1) should be added to 10 kg of water so that the solution freezes at -10°C?(Kf for water = 1ˑ86 K kg mol-1).

Section B – 20 Marks

Question 2 [2]

(i) Arrange the following alcohols in order of decreasing activity towards Lucas’ reagent.
2-butanol, 2-methyl-2-propanol and 1-butanol

(ii) Ethanol has a higher boiling point than methoxymethane. Justify the statement.

Question 3 [2]

Give a reason for each of the following:

(i) The size of the trivalent cations in Lanthanoid series decreases steadily as the atomic number increases.
(ii) The third ionization energy of manganese (Z = 25) is unexpectedly high.

Question 4 [2]

Give balanced chemical equations to convert the following:

(i) Benzene to biphenyl
(ii) Propene to propane -1-ol

Question 5 [2]

Account for the following:

(i) Salts of cuprous (Cu+) ion are colourless whereas the salts of cupric (Cu2+) ion are coloured.
(ii) Zinc is not regarded as a transition element. (at. no. of Zn = 30)

Question 6 [2]

Two compounds, D-2-chlorobutane and L-2-chlorobutane, are enantiomers of each other.
Name one physical property that is:

(i) same for D-2-chlorobutane and L-2-chlorobutane.
(ii) different for D-2-chlorobutane and L-2-chlorobutane.

Question 7 [2]

(i) A rusted piece of iron undergoes electrochemical reactions. Write the chemical reaction taking place at:

(a) the electrode that behaves as an anode.
(b) the electrode that behaves as a cathode.

(ii) Given that the standard reduction potential for Al3+/Al = -1ˑ66 V and ½ I2/I- = 0ˑ54V, what will be the standard potential of the cell made by using Al3+ and I- ?

Question 8 [2]

(i) What happens when (write chemical reactions only)

(a) Diethyl ether is treated with phosphorous pentachloride.
(b) Ethyl alcohol is treated with methyl magnesium bromide.

(ii) An organic compound [A] having molecular formula C6H6O gives a characteristic colour with aqueous FeCl3 solution. [A] on treatment with CO2 and NaOH at 400K under pressure gives [B] which on acidification gives compound [C]. [C] reacts with acetyl chloride to give [D] which is a popular pain killer. Identify the compounds [A], [B], [C] and [D].

Question 9 [2]

John was making noodles in boiling water. When he added common salt (NaCl) to boiling water, the water stopped boiling for a short while. If John had added 15ˑ0g of NaCl to 250ˑ0g of water, calculate the boiling point of solution assuming that NaCl dissociates completely in water. (Kb for water = 0ˑ512K kg mol-1 , molecular mass of NaCl = 58ˑ44 g mol-1).

Question 10 [2]

(i) Aromatic aldehydes do not give a reddish-brown precipitate on heating with Fehling solution. Give a reason.
(ii) Why is benzaldehyde less reactive to electrophilic substitution reactions than benzene?

Question 11 [2]

(i) Give a reason to explain why transition metals can act as a good catalyst.
(ii) Scandium (Z = 21) does not exhibit variable oxidation states and yet it is regarded as transition element. Why?

Section C – 21 Marks

Question 12 [3]

The data in the table given below was obtained in a series of experiments on the rate of the reaction between compounds [A] and [B] at a constant temperature:

Show how this data can be used to deduce the rate expression for the reaction between [A] and [B].

Question 13 [3]

Arrange the following compounds:
C6H5NH2, (C2H5)2NH, (C2H5)3N, C2H5NH2.

(i) in the increasing order of their basic strength in water.
(ii) in a decreasing order of their basic strength in gas phase.

Question 14 [3]

(i) What products are obtained when sucrose is subjected to acid hydrolysis?
(ii) Why are Vitamin B and Vitamin C essential for us?
(iii) On being heated, egg white becomes solid and opaque. Give a reason.

Question 15 [3]

Water vapour and liquid water are in equilibrium in a container. At room temperature, the vapour pressure of water is 25 mm of Hg. The volume of water is V ml.

(i) What will be the vapour pressure of water if the volume of water is reduced to V/4 ml without any change in temperature? Give a reason.
(ii) Will there be a change in vapour pressure if more water (at room temperature) is added to the container? Give a reason.

Question 17 [3]

(i) How will the following be obtained? (Give chemical equation)

(a) Picric acid from Phenol
(b) Ethyl acetate from ethanol
(c) Anisole from sodium phenoxide

(ii) Explain the mechanism of acid catalysed dehydration of ethanol to yield the corresponding alkene.

Question 18 [3]

(i) The half-life period (t ½) for decay of radioactive 14C is 5730 years. An ancient piece of wood has only 80% of the 14C found in a living tree. Calculate the age of the piece of wood.

(ii) The rate of most of the reactions becomes double when the temperature is raised from 298K to 308K. Calculate the activation energy. (R = 8ˑ314 J K-1 mol-1)

Section D – 15 Marks

Question 19 [5]

(i) Give a reason for each of the following:

(a) Formaldehyde does not undergo aldol condensation, but acetaldehyde does.

(b) Chloroacetic acid is stronger acid than acetic acid.

(ii) An organic compound with the molecular formula C7H6O gets oxidised by Tollens’ reagent. It does not respond to Fehling test but can undergo the Cannizzaro reaction.
Identify the compound. Show how you used the above information to identify the compound.

Question 20 [5]

(i) When one mole of an isomer of the complex [Cr(H2O)6]Cl3 is treated with AgNO3, it produces 1 mole of a white precipitate of AgCl.
Write the formula of this isomer of the complex and show how the metal-ligand bonding differs in the isomers.

(ii) A coordination compound shows d2sp3 hybridisation. Identify the nature of ligand as weak or strong. What will be the geometry of the compound?

Question 21 [5]

(i)
(a) Calculate the value of Eo cell and ∆Go that can be obtained from the following cell under the standard conditions at 25°C

(b) How much electricity in Faraday is required for the complete reduction of MnO4− ions present in 500 ml of 0ˑ5 M solution to Mn2+?

(a) The molar conductivity vs √C curve for Na2SO4, H2SO4, and NH4OH are shown below in random order

Identify the curve that corresponds to Na2SO4, H2SO4, and NH4OH.
Justify your answer.
(b) The molar conductivity (ꓥm) of a dilute solution of methanoic acid is 34ˑ1 S cm² /mol. Calculate its degree of dissociation.
(Given λ°(H+) = 349ˑ6 S cm²/mol and λ°(HCOO-) = 54ˑ6 S cm²/mol)