Jkbose 12th Chemistry Most Important Questions 2026 - Bi-Annual Private Exam
LONG ANSWER TYPE QUESTIONS
☑️ Define elevation in B.P. How can you calculate the molecular mass of a non-volatile solute with it?
☑️ Define Osmotic Pressure. How is it determined by Berkeley-Hartley method?
(i) Define :
(a) Mole fraction
(b) Molality
(c) Molarity
☑️ Calculate the mole fraction of ethylene glycol (C₂H₆O₂) in a solution containing 20% of C₂H₆O₂ by mass.
☑️ State and explain Raoult’s law
☑️ What do you understand by Colligative properties of a solution ? Explain briefly osmosis and osmotic pressure.
☑️ What is an electrochemical cell ? Describe working of Daniell cell.
☑️ Write a short note on
- a) Fuel cells
- b) Corrosion
☑️ Give three methods of preparing aldehydes and two methods for acetone.
Name Reactions (With Equations)
☑️ Write a brief account (with equations) of:
(a) Aldol condensation
(b) Cannizzaro reaction
(c) Rosemund reduction
☑️ Describe Cannizzaro’s reaction.
(a) Esterification
(b) Cannizzaro reaction
(c) Cross Aldol reaction
(d) Decarboxylation
(a) Benzyl alcohol
(b) 3-Nitrobenzoic acid
(c) Methyl benzoate
☑️ Explain why formic acid is stronger than acetic acid.
☑️ Discuss in detail the various factors which influence the rate of reaction?
☑️ State the following laws:
(a) Faraday first law of electrolysis
(b) Kohlrausch’s law of independent migration of ions.
☑️ (a) Write five methods for the preparation of aldehydes.
(b) How are aldehydes distinguished from ketones using Tollen and Fehling’s reagents ? Give chemical reactions
✅ Write a short note on
How will you prepare aldehydes from
(a) Ozonolysis of alkenes
(b) Acyl chloride (Rosenmund reduction)
(c) Nitriles (Stephen reaction)
(d) Toluene (Etard reaction)
✅ Define corrosion. Explain electrochemical theory of rusting. Name the important factors affecting corrosion.
✅ Discuss the following properties of transition elements.
(a) Magnetic Properties
(b) Oxidation States
✅ Explain why Aryl halides are less reactive than haloalkanes towards nucleophilic substitution reaction.
✅ Write the products formed when chlorobenzene under-goes the following reactions.
(a) Halogenation
(b) Nitration
(c) Sulphonation
(d) Friedel-Crafts alkylation with Methyl chloride
(e) Friedel-Crafts acylation with acetyl chloride
✅ Discuss in detail the various factors which influence the rate of reaction.
✅ State and explain Arrhenius equation. How the activation energy of a reaction can be determined by using this equation?
✅ Define molar conductivity of a substance. Explain how for weak and strong electrolytes, molar conductivity changes with dilution.
SHORT ANSWER TYPE QUESTIONS
☑️. What are electrochemical series? Write its applications.
☑️ Define:
-
Specific Conductivity
-
Equivalent Conductivity
-
Molar Conductivity
☑️ Explain construction and working of a Galvanic (Voltaic) Cell
☑️ Write and explain Nernst Equation
☑️ What is rate law?
☑️ Define rate constant. Write its units.
☑️ What is order of reaction?
☑️ Explain: First order reaction, Zero order reaction.
☑️ Explain collision theory.
☑️ State and explain Arrhenius equation.
🟢 What is Osmotic pressure? Show that Osmotic pressure is a colligative property.
🟢 What is electrolysis? State and explain Faraday's first law of electrolysis.
🟢 What is order of a reaction? Derive expression for the rate constant for the first order reaction.
🟢 Give important uses and applications of coordination compounds.
🟢 What happens when
🟢 Chlorobenzene is treated with methyl chloride in the presence of anhydrous AlCl₃.
☑️. Explain the methods of preparation of haloalkanes.
☑️. Give a brief account of the following reactions:
(i) Fitting Reaction
(ii) Wurtz Reaction
(iii) Wurtz–Fittig Reaction
☑️ Discuss the harmful effects and uses of D.D.T.
🟩 How will you distinguish between primary, secondary and tertiary alcohols by:
(a) Victor Meyer’s test
(b) Lucas test
🟩 Explain the following reactions with equations:
(i) Reimer–Tiemann Reaction
(ii) Kolbe’s Synthesis (Kolbe–Schmitt reaction)
(iii) Williamson Ether Synthesis
🟩 What are phenols? How do they differ from aromatic alcohols? Give suitable examples.
phenol into salicylaldehyde.
phenol into phenyl acetate
🟩 Explain the dehydration of ethanol with concentrated H₂SO₄ at 443 K and 413 K. Write chemical equations.
🟩. Why is an alkylamine more basic than ammonia?
🟩. What is Hinsberg's reagent? How is it used to distinguish amines?
🟩 What are amines? How are they classified?
🟩. What are diazonium salts? Write reaction of benzene diazonium chloride with KI (potassium iodide).
🟩. Explain diazotisation and coupling reactions with examples.
🟩 Define coordination number and ligand with examples.
🟩 Write IUPAC names of:
[Co(NH₃)₄]Cl₃
[Ni(CO)₄]
🟩. Explain Werner’s theory of coordination compounds.
🟩. What is difference between double salt and complex salt?
🟩 Write isomerism shown by coordination compounds.
🟩 Explain valence bond theory of octahedral complexes.
🟩. Explain crystal field theory for octahedral complexes.
🟩. Write applications of coordination compounds.
🟩. Explain structural isomerism and stereoisomerism in coordination compounds.
🟩. Discuss bonding in coordination compounds according to VBT and CFT.
☑️. What are monosaccharides? Give examples.
☑️. What are disaccharides? Give examples
☑️ Define amino acids. Give examples.
☑️. What are vitamins? Classify with examples.
☑️. Write functions of carbohydrates.
☑️. Discuss classification and functions of vitamins.
☑️ Why do transition metals show variable oxidation states?
☑️ Compare actinides with lanthanides.
☑️ Why are transition metals good catalysts?
☑️ Write preparation and properties of K₂Cr₂O₇.
☑️ Why are transition metals hard and have high melting points?
☑️ Discuss general characteristics of d-block elements.
☑️ Write important properties and uses of potassium dichromate.
✅ Formic acid (methanoic acid) is stronger acid than acetic acid (ethanoic acid). Explain.
✅ Define conductivity and molar conductivity for the solution of an electrolyte.
✅ Explain the following about transition metals :
(a) Magnetic behaviour
(b) Oxidation states
✅ How is potassium dichromate prepared from chromite ore ?
✅ Give its three oxidising properties.
Discuss briefly giving an example in each case the role of co-ordination compounds in :
(a) Biological system
(b) Medicinal chemistry
✅) How will you convert ethyl bromide to :
(a) Ethane
(b) Ethoxyethane
(c) Ethanenitrile ?
✅ Define electrode potential. What are the factors which affect the electrode potential?
✅ Define the following terms:
(a) Molal depression constant (K)
(b) Molal elevation constant (Kₑ)
✅ Name the following coordination compounds according to IUPAC system of nomenclature:
(a) [Co (NH₃)₄ (H₂O) Cl] Cl₂
(b) K₂ [NiCl₄]
(c) [Cr (NH₃)₅ Cl₂ (en)] Cl
✅ What are the characteristics of the transition elements and why are they called transition elements? Which of the d-block elements may not be regarded as the transition elements?
✅ How does the phenol react with Bromine (Br₂) in
(a) Aqueous medium
(b) Less polar solvent like CS₂
✅ What is Aldol condensation? Explain with an example.
✅ How amines are prepared from nitro-compounds and nitriles?
✅ Why aromatic amines are weaker bases than aliphatic amines?
✅ What are carbohydrates and how are they classified on the basis of their behaviour on hydrolysis?
✅ Explain why transition metal ions usually show paramagnetic behaviour ?
✅ What happens when acidified KMnO₄ reacts with
(a) H₂S
(b) Oxalic acid
(c) KNO₂ ?
✅ Define cis and trans isomerism. Draw the cis and trans isomers of [Co(NH₃)₄Cl₂]⁺ ion.
✅ How will you convert ethyl bromide to :
(a) Ethoxyethane
(b) Ethane
(c) Ethanol
✅ How will you distinguish between primary, secondary and tertiary alcohols by Victor Meyer's test ? Give chemical reactions.
✅ What is Diazotisation ? Discuss its mechanism.
✅ What are Carbohydrates ? How are they classified ?
(b) Ethyl chloride is treated with aqueous KOH
(c) Bromobenzene is treated with methyl bromide and sodium in the presence of dry ether.
✅ Write the mechanism of acid dehydration of ethanol to yield ethene.
✅ Describe a method (Hinsberg test) for the identification of Primary, Secondary and Tertiary amines. Also write chemical equations of the reactions involved.
✅ (a) What do you understand by the term glycosidic linkage?
(b) Which sugar is called invert sugar? Why is it called so?
✅ Write the important structural and functional differences between DNA and RNA.
