ISC (Science)
Academic Year: 2025-2026
Date: March 2026
Advertisements
Instructions to Candidates:
- You are allowed an additional fifteen minutes for only reading the question paper.
- You must NOT start writing during the reading time.
- This question paper has 9 printed pages.
- It is divided into four sections and has twenty one questions in all.
- Answer all questions.
- Section A has fourteen subparts. Each question carries 1 mark.
- While attempting Multiple Choice Questions in Section A, you are required to write only ONE option as the answer.
- Section B has ten questions. Each question carries 2 marks.
- Section C has seven questions. Each question carries 3 marks.
- Section D has three questions. Each question carries 5 marks.
- Internal choices have been provided in one question each in Sections B, C and D.
- The intended marks for questions are given in brackets [ ].
- All working, including rough work, should be done on the same sheet as, and adjacent to the rest of the answer.
- Balanced equations must be given wherever possible and diagrams where they are helpful.
- When solving numerical problems, all essential workings must be shown.
- In working out problems, use the following data.
Gas constant R = 1.987 cal deg−1 mol−1 = 8.314 JK−1 mol−1
= 0.0821 dm3 atm K−1 mol−1, 1 l atm = 1 dm3 atm = 101.3 J.
1 Faraday = 96500 coulombs. Avogadro’s number= 6.023 × 1023.
Fill in the blanks by choosing the appropriate word(s) from those given in the brackets:
[electrophilic, four, 4-bromophenol, first, alc. AgCN, decreases, 2,4,6-tribromophenol, nucleophilic, two, zero, alc. KCN, increases]
The addition of a non-volatile solute to a pure solvent ______ its vapour pressure and ______ its boiling point.
Chapter:
Fill in the blanks by choosing the appropriate word/words from those given in the brackets:
(more than, primary, cathode, Lucas reagent, two, four, less than, Grignard’s reagent, tertiary anode, zero, equal to, three)
When the concentration of reactant of first order reaction is doubled, the rate of reaction becomes ______ times, but for a ______ order reaction, the rate of reaction remains the same.
Chapter:
Fill in the blanks by choosing the appropriate word(s) from those given in the brackets:
[electrophilic, four, 4-bromophenol, first, alc. AgCN, decreases, 2,4,6-tribromophenol, nucleophilic, two, zero, alc. KCN, increases]
Phenol when treated with bromine water produces ______ which is an example of ______ substitution reaction.
Chapter:
Fill in the blanks by choosing the appropriate word(s) from those given in the brackets:
[electrophilic, four, 4-bromophenol, first, alc. AgCN, decreases, 2,4,6-tribromophenol, nucleophilic, two, zero, alc. KCN, increases]
Methyl chloride on treatment with ______ gives methyl cyanide whereas on treatment with ______, it gives methyl isocyanide.
Chapter:
The sum of the coordination number and oxidation number of metal ‘M’ in the complex [M(en)2Cl2] is ______.
6
8
9
10
Chapter:
Which of the following orders is correct in the spectrochemical series of ligands?
(P) I− < NH3 < CN− < CO
(Q) CO < I− < NH3 < CN−
(R) NH3 < CO < CN− < I−
(S) F− < NH3 < CN− < CO
Only (Q) and (S) are correct.
Only (P) and (S) are correct.
Only (P) and (Q) are correct.
Only (P) and (R) are correct.
Chapter:
When chlorobenzene is heated with aq. ammonia in the presence of Cu2O at high pressure, it gives ______.
aniline
phenyl isocyanide
diphenyl
diphenylamine
Chapter:
Hydrolysis of sucrose is called ______.
inversion
hydration
esterification
saponification
Chapter:
An organic compound with the molecular formula C3H6O does not give the silver mirror test with Tollen’s reagent but gives an oxime with hydroxylamine. The compound is ______.
CH3CH2CHO
CH3 – CO – CH3
CH2 = CH – CH2OH
CH2 = CH – O – CH3
Chapter:
Assertion: 0.1 M sucrose solution has higher depression in the freezing point than 0.1 M urea solution.
Reason: Depression in freezing point is not a colligative property.
Both Assertion and Reason are true and Reason is the correct explanation for Assertion.
Both Assertion and Reason are true but Reason is not the correct explanation for Assertion.
Assertion is true and Reason is false.
Both Assertion and Reason are false.
Chapter:
Assertion: Methoxyethane reacts with HI at 373 K to give ethanol and iodomethane.
Reason: Reaction of unsymmetrical ether with HI follows SN2 mechanism.
Both Assertion and Reason are true and Reason is the correct explanation for Assertion.
Both Assertion and Reason are true but Reason is not the correct explanation for Assertion.
Assertion is true and Reason is false.
Both Assertion and Reason are false.
Chapter:
Read the passage carefully and answer the questions that follow.
|
Vishal set up an experiment to find the resistance of aqueous KCl solution for different concentrations at 298 K using a conductivity cell connected to a Wheatstone bridge. He fed the Wheatstone bridge with A.C. power in the audio frequency range of 550 to 5000 cycles per second. Once the resistance was calculated from the null point, he also calculated the conductivity (κ) and molar conductivity (Λm) and recorded his readings in tabular form, which is given below.
|
- Why did the molar conductivity increase, though the conductivity decreased with dilution?
- If molar conductivity at infinite dilution `(Λ_m^o)` of KCl is 150.0 S cm2 mol−1, calculate the degree of dissociation of 0.01 M KCl.
- The conductivity of a 0.01 M solution of acetic acid at 298 K is 1.65 × 10−4 S cm−1. Calculate the molar conductivity of the solution.
Chapter:
Consider yourself a research scholar in the forensic science department studying the age of a dead biological sample. During one of the studies, you found that the sample decomposed by following first order kinetics.
If 50% of the sample is decomposed in 120 minutes, how long will it take for 90% of the sample to decompose?
Chapter:
Write the chemical equation to convert the following:
Aniline to bromobenzene.
Chapter:
How the following conversion can be carried out?
Ethyl chloride to propanoic acid.
Chapter:
Using IUPAC norms, write the formula for the following:
Hexaamminecobalt (III) sulphate
Chapter:
Using IUPAC nomenclature, write the formula of the following:
tetraaquadichloridochromium(III) nitrate
Chapter:
When 2 g of benzoic acid (C6H5COOH) is dissolved in 25 g of benzene, it shows a depression in freezing point equal to 1.62 K. Molal depression constant for benzene is 4.7 K kg mol−1.
What is the percentage association of acid if it forms a dimer in solution?
Chapter:
Convert the following by giving a chemical equation:
Phenol to salicylaldehyde.
Chapter:
How will you convert the following (write chemical equation):
Formaldehyde to ethanol.
Chapter:
The molar conductivities at infinite dilution `(Λ_m^∞)` for NaI, CH3COONa and (CH3COO)2Mg are 126.9, 91.0 and 187.8 ohm−1 cm2 mol−1 respectively, at 25°C. What is the molar conductivity of MgI2 at infinite dilution?
Chapter:
Which divalent metal ion in a weak field ligand has maximum paramagnetic character among the first transition metal series (3d series)? Why?
Chapter:
The melting and boiling points for Zn, Cd, and Hg are low. Why?
Chapter:
What happens when a carbonyl compound is treated with zinc amalgam and concentrated hydrochloric acid? Give the chemical equation and write the name of the reaction.
Chapter:
Advertisements
Write a chemical equation to convert the following:
Acetic acid to acetaldehyde.
Chapter:
How will you bring about the following conversion? (Give equation).
Formaldehyde to urotropine.
Chapter:
It is generally observed that the rate of a chemical reaction becomes double with every 10°C rise in temperature. If the generalisation holds true for a reaction in the temperature range of 298 K to 308 K, what would be the value of activation energy (Ea) for the reaction?
Chapter:
Write the chemical equation for the following named organic reaction:
Hofmann’s degradation reaction
Chapter:
Write the chemical equation for the following named organic reaction:
Balz-Schiemann reaction
Chapter:
Write the reaction involved in the preparation of phenol from benzene sulphonic acid.
Chapter:
How will you convert the following? (Write chemical equation.)
Ethyl alcohol from ethylamine.
Chapter:
How will you prepare diethyl ether by dehydration of alcohol?
Chapter:
Complete and balance the following equation:
\[\ce{K2Cr2O7 + FeSO4 + H2SO4 ->}\]______ + _____ + ______ + ______
Chapter:
Complete and balance the following equation:
\[\ce{KMnO4 + KI + H2SO4 ->}\]______ + ______ + ______ + ______
Chapter:
Explain how the colour of K2Cr2O7 solution depends on pH of the solution.
Chapter:
Write the structure of the major organic product in the following reaction:
\[\ce{C6H5ONa + C2H5Cl ->}\]
Chapter:
Complete the following reaction:
\[\ce{C2H5NH2 + CHCl3 + KOH (alc{.}) ->[Warm]}\]
Chapter:
Write the structure of the major organic product in the following reaction:
\[\ce{CH3CH2CH2Cl + NaI ->[acetone][heat]}\]
Chapter:
Which vitamin deficiency is responsible for xerophthalmia and night blindness?
Chapter:
What are the expected products of hydrolysis of lactose?
Chapter:
When grapes are placed in a salt solution, they tend to shrink. Why?
Chapter:
A 0.01 M solution of NaCl is diluted by adding water. What will happen to its specific conductivity and molar conductivity?
Chapter:
Is it safe to stir a 1 M AgNO3 solution with a copper spoon? Explain.
(Given: `E_((Cu^(2+)//Cu))^°` = +0.34 V, `E_((Ag^+//Ag))^°` = +0.80 V)
Chapter:
Two metals A and B have standard reduction potential values of −2.37 V and +0.80 V, respectively. Which of these will liberate H2 gas from dilute HCl?
Chapter:
Calculate the values of Ecell and ΔG for the following cell reaction at 25°C:
\[\ce{Zn_{(s)}/Zn^{2+}_{(0.0004 M)} || Cd^{2+}_{(0.2 M)}/Cd_{(s)}}\]
(Given, \[\ce{E^°_{Zn^{2+}/Zn}}\] = −0.763 V and \[\ce{E^°_{Cd^{2+}/Cd}}\] = −0.403 V, 1 Faraday = 96,500 coulombs, R = 8.314 JK−1 mol−1 )
Chapter:
Calculate how long it will take to deposit 1.0 g of chromium when a current of 1.25 ampere flows through a solution of chromium (III) sulphate. (Atomic weight of Cr = 52, 1 Faraday = 96,500 coulombs)
Chapter:
Advertisements
The unit of the rate constant of a reaction is the same as that of its rate of reaction. Find the order of this reaction.
Chapter:
Give one example of a pseudo first-order reaction.
Chapter:
How will the rate of reaction be affected when the surface area of the reactant is reduced?
Chapter:
Identify the compounds [A], [B] and [C] in the following reaction:
\[\ce{C6H5CONH2 ->[Br2/aq{.} KOH][][A]->[NaNO2 {+} HCl (ice cold)][][B]->[Cu2Cl2 {+} HCl][][C]}\]
Chapter:
Identify the compounds [A], [B] and [C] in the following reaction:
\[\ce{CH3C≡N ->[4{[H]}] [A]->[HNO2 (0°C)] [B]->[SOCl2 (Pyridine)] [C]}\]
Chapter:
What happens when propanone is treated with CH3MgBr and then hydrolysed?
Chapter:
What happens when methanal undergoes cannizzaro reaction?
Chapter:
Give the chemical equation:
What happens when acetic acid reacts with SOCl2 and the main product obtained is reduced with H2 in the presence of Pd/BaSO4?
Chapter:
An aromatic compound [A] gives a buff-coloured precipitate on treatment with neutral FeCl3 solution. Compound [A] reacts with thionyl chloride to give compound [B], which on reacting with ammonia followed by heating gives compound [C]. Compound [C] on treatment with bromine in KOH forms [D] with molecular formula C6H7N and has a characteristic odour. Identify the compounds [A], [B], [C] and [D].
Chapter:
An aqueous solution contains 0.63 g of protein in 300 cm3 of water. The osmotic pressure of the solution at 300 K is 1.29 × 10−3 atm. Calculate the molecular mass of protein.
(Given R = 0.0821 Lit atm K−1 mol−1)
Chapter:
What mass of ethylene glycol must be added to 5.50 kg of water to lower the freezing point of water from 0°C to −10.0°C?
(Kf for water = 1.86°C kg mol−1, molecular weight of ethylene glycol = 62.0 g mol−1)
Chapter:
The outer shells of two eggs are removed. One of the eggs is placed in pure water and the other is placed in saturated solution of sodium chloride. What will be observed and why?
Chapter:
What would be the value of van’t Hoff factor for a dilute solution of K2SO4 in water?
Chapter:
When a coordination compound CoCl3.6NH3 is mixed with AgNO3, 3 moles of AgCl are precipitated per mole of the compound. Write the structural formula of the coordination compound.
Chapter:
Predict the number of unpaired electrons in [Fe(H2O)6]3+ and [Fe(CN)6]3− based on crystal field theory.
Chapter:
Draw a diagram to show the splitting of d-orbitals in a tetrahedral crystal field.
Chapter:
Write the formula for the following:
Linkage isomer of [CoCl(en)2(NO2)]Cl2
Chapter:
Write the formula for the following:
Ionisation isomer of [CoBr(NH3)5]SO4
Chapter:
For the complex compound [Fe(en)2Cl2]Cl, identify the following:
Oxidation state
Chapter:
For the complex compound [Fe(en)2Cl2]Cl, identify the following:
Hybridisation of the central metal atom
Chapter:
For the complex compound [Fe(en)2Cl2]Cl, identify the following:
Magnetic behaviour of the complex
Chapter:
For the complex compound [Fe(en)2Cl2]Cl, identify the following:
Geometry of the complex
Chapter:
Draw the geometrical isomers of complex [Pt(en)2Cl2]2+.
Chapter:
On the basis of crystal field theory, write the electronic configuration for d4 with a strong field ligand for which Δ0 > P.
Chapter:
Submit Question Paper
Help us maintain new question papers on Shaalaa.com, so we can continue to help studentsonly jpg, png and pdf files
CISCE previous year question papers ISC Class 12 Chemistry (Theory) with solutions 2025 - 2026
Previous year Question paper for CISCE ISC Class 12 -2026 is solved by experts. Solved question papers gives you the chance to check yourself after your mock test.
By referring the question paper Solutions for Chemistry (Theory), you can scale your preparation level and work on your weak areas. It will also help the candidates in developing the time-management skills. Practice makes perfect, and there is no better way to practice than to attempt previous year question paper solutions of CISCE ISC Class 12.
How CISCE ISC Class 12 Question Paper solutions Help Students ?
• Question paper solutions for Chemistry (Theory) will helps students to prepare for exam.
• Question paper with answer will boost students confidence in exam time and also give you an idea About the important questions and topics to be prepared for the board exam.
• For finding solution of question papers no need to refer so multiple sources like textbook or guides.
