ISC Chemistry 2025 Practice Paper with Answers
All 97 questions of the ISC Chemistry 2025 Practice Paper, in printed order. Open a question to read it in full and see its answer.
- Q1 Which of the following reactions will NOT form an ether through Williamson's synthesis? I… 1 mark · MCQ
- Q2 The correct order of acidic strength among the following organic compounds is: 1 mark · MCQ
- Q3 For the reaction: What are X and R respectively in the given reaction? 1 mark · MCQ
- Q4 An element [X] has an outer electronic configuration as $3d^5 4s^2$. The maximum oxidation state and most common oxidising state… 1 mark · MCQ
- Q5 Secondary amines can be prepared by reduction. Identify the compound that will form a secondary amine on reaction with… 1 mark · MCQ
- Q6 Which of the following is most basic? 1 mark · MCQ
- Q7 Depression in freezing point is a colligative property. At the same concentration in aqueous solution, select the solution that… 1 mark · MCQ
- Q8 When the molality of the dilute solution is multiplied by four, what will be the resulting effect on the molal depression… 1 mark · MCQ
- Q9 If Sodium nitrate is completely dissociated into cations and anions in aqueous solution, the change in freezing point of water… 1 mark · MCQ
- Q10 For a reaction $\text{A} \rightarrow \text{B} + \text{C}$, when a student X doubled the concentration of ‘A’, the rate of… 1 mark · MCQ
- Q11 Which of the following combinations is INCORRECT regarding order and molecularity of a hypothetical reaction? 1 mark · MCQ
- Q12 With which of the following reagent both glucose and fructose will produce the same product? 1 mark · MCQ
- Q13 What kind of bond will be formed when glycine and alanine are condensed together? 1 mark · MCQ
- Q14 The reaction of the compound A with $\text{NH}_3$ gives an aromatic amine B. This amine on treatment with nitrous acid forms a… 1 mark · MCQ
- Q15 Rahul wants to prepare chloroform in the laboratory using ethanol. The correct order of preparation is: 1 mark · MCQ
- Q16 The C-X bond length in haloarenes is shorter due to: 1 mark · MCQ
- Q17 How much charge is required for the reduction of $1\text{ mole}$ of $\text{Cu}^{2+}$ to $\text{Cu}$? 1 mark · MCQ
- Q18 The above graph indicates the variation of molar conductivity of different electrolytes. $\text{NaCl}$, $\text{CH}_3\text{COOH}$… 1 mark · MCQ
- Q19 On adding silver nitrate solution to $\text{CoBr}_2\text{Cl}\cdot 4\text{NH}_3$, 1 mole of light-yellow precipitate of compound X… 1 mark · MCQ
- Q20 Gia applied magnetic field around $[\text{Fe}(\text{H}_2\text{O})_6]^{2+}$ and $[\text{Fe}(\text{CN})_6]^{4-}$, she found that… 1 mark · MCQ
- Q21 Toluene reacts with chromyl chloride in $\text{CCl}_4$ to give compound (X). Which of the following test is most likely to be… 1 mark · MCQ
- Q22 Which of the following compound is the most and least reactive towards nucleophilic substitution reaction respectively? (I)… 1 mark · MCQ
- Q23 From a plot of rate (Y-axis) and concentration (X- axis), a student concluded that the order of reaction is zero. What he must… 1 mark · MCQ
- Q24 Electrophilic substitution reactions in haloarenes takes place in ortho and para positions and the major product is para… 1 mark · Assertion-reason
- Q25 Benzaldehyde on nitration gives Ortho and para nitro benzaldehyde. 1 mark · Assertion-reason
- Q26 The half-life of a first order reaction does not depend on initial concentration of the reactant. 1 mark · Assertion-reason
- Q27 Ethanol is less acidic than water. 1 mark · Assertion-reason
- Q28 Nucleic acids are present in all living cells. 1 mark · Assertion-reason
- Q29 The orange colour of dichromate solution changes to ____ on heating with an alkali due to the formation of ____ ions. 1 mark · Fill in
- Q30 The $pK_a$ value of o-nitrophenol is ____ than p-nitrophenol and its acidic character is ____ than p-nitrophenol. 1 mark · Fill in
- Q31 ____ amines do not undergo acylation as they lack replaceable hydrogen whereas ____ amines undergo acylation reaction. 1 mark · Fill in
- Q32 The Van't Hoff factor for aqueous acetic acid is ____ than one while that of acetic acid in benzene is ____ than one. 1 mark · Fill in
- Q33 A first order reaction is half complete in 20 minutes, it will be 75% complete in ____ minutes and 87.5% complete in ____ minutes. 1 mark · Fill in
- Q34 Fibrous proteins are ____ in water whereas the globular proteins are ____ in water. 1 mark · Fill in
- Q35 Elimination reactions of Haloalkanes takes place in the presence of ____ $\text{KOH}$ at ____ position of carbon atom. 1 mark · Fill in
- Q36 When the concentration of the solution of a weak electrolyte is ____, its ____ conductivity increases. 1 mark · Fill in
- Q37 The melting point of acetic acid is ____ than propanoic acid whereas the boiling point of acetic acid is ____ than propanoic acid. 1 mark · Fill in
- Q38 The complex ion $[\text{Co}(\text{NH}_3)_5(\text{NO}_2)]^{2+}$ is ____ stable towards an acid than… 1 mark · Fill in
- Q39 The boiling point (b.p.) of methyl amine, ethane and methanol is 265K, 185K and 333K respectively. How can one account for these… 2 marks · Short answer
- Q40 Do you think $[\text{Co}(\text{en})_3]^{3+}$ will show optical isomerism? If yes, draw the possible isomers and name them. If no… 2 marks · Short answer
- Q41 Based on Valence Bond Theory (VBT), discuss the hybridisation, shape and charge on metal in $[\text{Ni}(\text{CO})_4]$ complex… 2 marks · Short answer
- Q42 Two students X and Y were studying the basicity of compounds. X wrote that ammonia is less basic than methylamine whereas Y wrote… 2 marks · Short answer
- Q43 A student has carried out a suitable test to differentiate between: (a) ethyl amine and diethyl amine (b) ethanol and ethyl… 2 marks · Short answer
- Q44 Give a reason for each given below: Except glycine, all other naturally occurring $\alpha$-amino acids are optically active… 2 marks · Short answer
- Q45 Answer the following: Complete: $\text{CHO}-(\text{CHOH})_4-\text{CH}_2\text{OH} + \text{HI} \rightarrow \text{______}$ Enzymes… 2 marks · Short answer
- Q46 Predict the order of reaction and name X and Y axes. 2 marks · Short answer
- Q47 Find the three-fourths life, $t_{3/4}$ of a first order reaction, $k=7.4\times 10^{-5}\text{ s}^{-1}$. 2 marks · Numerical
- Q48 Study the graph given below and label the numbers: 2 marks · Short answer
- Q49 Rohan arranged three coulometers in series and passed one faraday of charge for a definite time to all three electrolytes as… 2 marks · Short answer
- Q50 Yash measures the conductivity of two different solutions of 1M Ethanoic acid and 1M HCl each at $25^\circ\text{C}$. Will he… 2 marks · Short answer
- Q51 The standard reduction potentials of the following electrodes are given below. Answer the questions that follow: Electrodes SRP… 2 marks · Short answer
- Q52 From the organic compounds given below: I. Acetophenone II. Benzaldehyde III. Benzophenone Arrange the compounds in the… 2 marks · Short answer
- Q53 How will you prepare the following compounds? Give chemical reaction for: Butan-2-one from propanoic acid. m-chlorotoluene from… 2 marks · Short answer
- Q54 Give reason: d-block elements exhibit larger number of oxidation state than f-block elements. Increase in atomic number does not… 2 marks · Short answer
- Q55 Halides of transition elements in higher oxidation states are more covalent. Give reason. 2 marks · Short answer
- Q56 Write equation for the following observations: Potassium permanganate on reaction with potassium iodide in acidic medium releases… 2 marks · Short answer
- Q57 Answer the following: What is meant by hydroboration –oxidation reaction? Explain with an equation to show the final product… 2 marks · Short answer
- Q58 You are provided with KOH (alc. and aq), $\text{Cl}_2$, HBr, acidified $\text{K}_2\text{Cr}_2\text{O}_7$, NaOH and soda lime… 2 marks · Short answer
- Q59 Answer the following: What is the significance of Van’t Hoff factor? Devise the relationship between Van’t Hoff factor and degree… 2 marks · Short answer
- Q60 Observe the following diagram and answer the questions that follows: In which direction, the flow of solvent will take place… 2 marks · Short answer
- Q61 2.517 g of Naphthalene is dissolved in 150 g $\text{CS}_2$, the solution boils at 319.70 K. The boiling point of $\text{CS}_2$ is… 2 marks · Numerical
- Q62 Given below are the two types of mechanism of the reaction: Answer the following questions: Why is the product obtained in (A)… 2 marks · Short answer
- Q63 This box gives a list of aldehydes and ketones. Choose the appropriate aldehyde/ ketone that reacts with $\text{CH}_3\text{MgBr}$… 3 marks · Short answer
- Q64 Give reason: The $K_a$ for p- nitro hydroxy benzene is $6.9 \times 10^{-8}$ whereas o-nitro benzene is $6.0 \times 10^{-8}$… 3 marks · Short answer
- Q65 Mention True or False and correct the wrong statements. The observed order of basic strength of amines is… 3 marks · Short answer
- Q66 In the box certain reagents are given in the form of clues: 'dehydrating agent, alkali dissolved in alcohol, Primary amine… 3 marks · Short answer
- Q67 Answer the following: A patient was given a certain amount of iodine-131 as a part of a diagnostic procedure for thyroid… 3 marks · Short answer
- Q68 Answer the following questions: Aman and Rohan were working on the kinetics involved in decomposition of hydrogen peroxide in the… 3 marks · Short answer
- Q69 Answer the following: Observe the structures of protein given below and answer the questions that follows: (i) Which type of… 3 marks · Short answer
- Q70 Answer the following questions: Two students took the solution of same amino acid at different pH and applied potential… 3 marks · Short answer
- Q71 The molecular shape of $[\text{Ni}(\text{CO})_4]$ is tetrahedral while that of $[\text{Ni}(\text{CN})_4]^{2-}$ is square planar… 3 marks · Short answer
- Q72 Nandini wants to electroplate her bracelet with silver. She gives the bracelet to an artist. After electroplating she gets the… 3 marks · Numerical
- Q73 3-bromo 3-methylhexane reacts with aq. KOH to give racemic mixture of products. Identify the type of reaction mechanism. Draw the… 3 marks · Short answer
- Q74 Which compound in each of the following pairs will react faster by $S_N2$ mechanism with –OH and why? $\text{CH}_3\text{Br}$ or… 3 marks · Short answer
- Q75 50 mg of $\text{Na}_2\text{SO}_4$ is dissolved in 3 litres of water at $27^\circ\text{C}$. What would be the osmotic pressure for… 3 marks · Numerical
- Q76 During a study trip, students visited a lake and took out water sample which was rich in potassium chloride salt. They performed… 3 marks · Numerical
- Q77 A student X was doing an experiment by taking 0.15 g acetic acid in 40 g of benzene. He suddenly observed that the freezing point… 3 marks · Numerical
- Q78 Starting with acetic acid, discuss the role of one F and one Cl groups play on the acidity of the acid when they replace a… 3 marks · Short answer
- Q79 A scientist while working in the lab accidently removed the labels from the carboxylic acid bottles and phenol. He had three… 3 marks · Short answer
- Q80 Geet has set-up the following galvanic cell by taking the electrolyte solution of $\text{Pb}(\text{NO}_3)_2$ and $\text{CrCl}_3$… 3 marks · Short answer
- Q81 Answer the following: Graphical method fails to give the value of molar conductivity at infinite dilution of weak electrolyte… 3 marks · Short answer
- Q82 Observe the following graph for ionisation enthalpies of first, second and third transition series. Answer the following… 3 marks · Short answer
- Q83 Vitamins are required in very small amount for the healthy growth of organisms. When a person does not get a particular vitamin… 3 marks · Short answer
- Q84 The concept of Osmosis is frequently used in medical field. On the other hand, reverse osmosis has also found application in… 3 marks · Short answer
- Q85 Chloroform was synthesised in the year 1847. It was mainly used in the medicine industry. When exposed to sunlight it forms a… 3 marks · Short answer
- Q86 Ships, being exposed to saltwater and atmospheric conditions, are highly susceptible to rust and corrosion. This is one method… 3 marks · Short answer
- Q87 Sodium ferrocyanide is used as anti-caking agent in salts and salt substitute. Due to contact with atmospheric moisture, table… 3 marks · Short answer
- Q88 Food and drug administration (FDA) has approved that Ethylenediamine tetra acetate (EDTA) is a medication in the treatment of… 3 marks · Short answer
- Q89 Alcohol and phenols are hydroxy derivatives of hydrocarbons. Both have the tendency to form intermolecular hydrogen bonding… 3 marks · Short answer
- Q90 Transition metals exhibit different oxidation states in their different types of compounds. Due to incompletely filled d-orbitals… 3 marks · Short answer
- Q91 Nucleic acids are present in the nuclei of all living cells. DNA analysis is vital in crime scene situations. RNA is essential… 3 marks · Short answer
- Q92 Vapour pressure plays an important role in calculating boiling point and the freezing point of solutions. In cold countries salt… 3 marks · Short answer
- Q93 Water pollution caused by toxic elements is one of the most important environmental problems in the world. The objectives of this… 5 marks · Case based
- Q94 Water phase change in soil causes severe damage to roads, canals, airport runways and other buildings. The freezing point is an… 5 marks · Case based
- Q95 The aldol condensation takes its name from aldol (3-hydroxybutanal) a name introduced by Wurtz who first prepared the… 5 marks · Case based
- Q96 ‘In 1915, a senior lecturer in Biochemistry at the University of Manchester named Dr. Chaim Weizmann invented a fermented process… 5 marks · Case based
- Q97 ‘Freidrich Wilhelm Georg Kohlrausch was a German physicist who studied the electrical conductivity of electrolytic solutions… 5 marks · Case based