HBSE Class 12 Chemistry Important Questions 2024

Class 12 Chemistry Important Question Answer solution with pdf. Here We Provides Class 1 to 12 all Subjects NCERT Solution with Notes, Question Answer, CBSE and HBSE Important Questions, MCQ and old Question Papers for Students.

HBSE ( Haryana Board ) Solution of Class 12 Chemistry important Question And Answer solution for 2024 exams.

HBSE Class 12 Chemistry Important Question 2024

HBSE Class 12 Chemistry Chapter 1 – Solutions Important Questions 2024

Q1. Define the terms : (i) Freezing point (ii) Molal depression constant

Q2. What is cause of depression in freezing point ?

Q3. 1.00 g of a non-electrolyte solute dissolved in 50 g of benzene lowered the freezing point of benzene by 0.40 K. The freezing point depression constant of benzene is 5.12 K kg mol-1. Find the molar mass of the solute. Most Important

Q4. Define the following terms: (i) Molality (ii) Osmotic pressure Most Important

Q5. Distinguish between Molarity and Molality. Which of the two is affected by temp. and why?

Q6. If the density of lake water is 1.25 g kg of water. Calculate the molality of m L-1 Na+ and contains 92 g of Na+ ions per ions in lake. Most Important

Q7. An antifreeze solution is prepared from 222.6 g of ethylene glycol C2H4(OH)2 and 200 g of water. Calculate the molality of the solution. If the density of the solution is 1.072 g/ml, then what shall be the molarity of the solution?

Q8. What is the molality of pure water?

Q9. If 5 g NaOH dissolved in 500 ml solution the molality of solution will be __________

Ans – 0.25 mol L-1

Q10. Calculate the Molality of 4.6 g ethanol (CH3CH2OH) in 200 g of benzene.

Q11. Calculate molality of 3 g ethanoic acid (CH3COOH) in 500 g of Benzene.

Q12. Concentrated HNO3 used in laboratory work is 68% HNO3 by mass in aqueous solution. What should be the molarity of such a sample of acid if density of solution is 1.504 gm L–1 ?

Q13. 4.0 gm of NaOH, dissolved in 500 ml of solution, calculate molarity of the solution. Most Important

Q14. Define the following terms: (i) Van’t Hoff factor (ii) Molarity

Q15. What is osmotic pressure? Show that it is a colligative property.

Q16. Define mole fraction and mass percentage.

Q17. Calculate the mole fraction of CH3OH in solution containing 30 % by mass in water.

Q18. State Henry’s law and give two applications.

Q19. Define the following:  (a) Henry’s Law  (b) Raoult’s law.

Q20. What is meant by positive and negative deviations from Raoult’s Law ?

Ans –When a solution does not obey Raoult’s law over the entire range of concentration, then it is called non-ideal solution. The vapour pressure of such a solution is either higher or lower than that predicted by Raoult’s law. If it is higher, the solution exhibits positive deviation and if it is lower, it exhibits negative deviation from Raoult’s law.

Q21. The boiling point of benzene is 353.23 K. When 1.80 g of a non-volatile solute was dissolved in 90 g of benzene, the boiling point is raised to 354.11 Κ. Calculate the molar mass of the solute. K for benzene is 2.53 K Kg mol-1.

Q22. On the basis of osmosis explain the condition edema.

Ans – People taking a lot of salt or salty food experience water retention in tissue cells and intercellular spaces because of osmosis. The resulting puffiness or swelling is called edema.

Q23. Define Osmosis and Reverse Osmosis with one example of each.

Q24. Give an example of a solid solution in which the solute is a gas.

Q25. What role does the Molecular interaction play in a solution of alcohol and water? Most Important

Q26. Why do gases always tend to be less soluble in liquids as the temperature is raised?

Q27. Calculate the mass of a non-volatile (Molar-mass 40 g mol–1 ) which should be dissolved in 114 g octane to reduce its vapour pressure to 80%.

Q28. Vapour pressure of water at 293 K is 17.535 mm Hg. Calculate the vapour pressure of water at 293 K when 25 g of glucose is dissolved in 450 g of water.

Q29. Briefly explain the effects of temperature on the solubility of solids in liquids.

Q30. Toluene is more easily nitrated than benzene. Explain.

Q31. Briefly discuss elevation in boiling point.

Q32. What is the cause of elevation in boiling point ?

Q33. Give two applications of Henry’s Law.

Q34. With the help of Henry’s law, explain the medical condition known as bends.

Q35. Write the expression for relative lowering in vapour pressure.

Q36. Why gases less soluble in liquids as temperature is raised ?

Q37. Molal Elevation constant is also known as ____________

Ans – Ebullioscopic Constant OR Boiling Point Elevation Constant

Q38. What are isotonic solutions ?

Ans – Two solutions having same osmotic pressure at a given temperature are called isotonic solutions.

HBSE Class 12 Chemistry Chapter 2 – Electrochemistry Important Questions 2024

Q1. State Faraday’s first law of electrolysis.

Q2. Explain the both laws of Faraday Electrolysis.

Q3. Explain Kohlrausch law with a suitable example.

Q4. What is Kohlrausch law? Discuss its applications with examples. Most Important

Q5. Why does the conductivity of a solution decrease with dilution ?

Q6. The cell in which the following reaction occurs: 2Fe3+ (aq) +2I (aq) 2Fe2+ (aq) + I2 (s) has E°(cell) = 0.236 V at 298 K. Calculate the standard Gibbs energy and the equilibrium constant of the cell reaction.

Q7. What is Molar conductivity ? Discuss their variation with concentration graphically.

Q8. The resistances of 0.05 M NaOH solution is 31.6 Ω and its cell constant is 0.357 cm–1. Calculate its conductivity and molar conductivity.

Q9. At 298 K the conductivity of 0.20 M KCl solution is 0.02485 ohm-1cm-1. Calculate the molar conductivity of the solution.

Q10. The molar conductivity of 0.02 mol L-1 methanoic acid is 46.1 S cm2 mol-1. Calculate its degree of dissociation. Given lambda λ°(H+) = 349.6 S cm2 mol-1 एवं λ°(HCOO) = 54.6 S cm2 mol-1

Q11. The Molar conductivity of 0.05 mol L-1 HCOOH is matrix 40 S cm2 mol-1 . Calculate its degree of dissociation and dissociation constant. Given λ°(H+) = 349.6 S cm2 mol-1 and λ°(HCOO) = 54.6 S cm2 mol-1

Q12. MnO4 → Mn+2 for this reaction, how many Faraday are required?

Q13. A solution of CuSO4 is electrolysed for 10 minutes with a current of 1.5 amperes. What is mass of copper deposited at Cathode ? (Cu63.5) Most Important

Q14. If a current of 0.5 ampere flows through a metallic wire for 2 hours, then how many electrons would flow through the wire ? Most Important

Q15. What are fuel cell ? Write reaction taking place in H2-O2 fuel cell.

Q16. Define fuel cell ? Give one use.

Q17. What is Corrosion ? Give factors which promotes corrosion and name the methods to prevent corrosion.
What is Corrosion ? Explain methods to prevent corrosion. Most Important

Q18. Write the Nernst equation for following cell: Sn(s) | Sn2+ || H+ | H2(g)(1bar) | Pt(s).

Q19. In the button cells widely used in watches and other devices the following reaction takes place:

Zn(s) + Ag2O(s) + H2O(l) Zn2+(aq) + 2Ag(s) + 2OH (aq)

Determine ΔrG° and E°cell for the reaction. E°Zn2+ | Zn = -.76V  E° Ag+ | Ag = +.80 V

Q20. A solution of Ni(NO3)2 is electrolysed between platinum electrode using a current of 5 ampere for 20 min., what mass of Ni is deposited at cathode ? (Ni = 58.7) Most Most Important

Q21. Describe the construction and working of Normal Hydrogen Electrode.

Q22. Calculate the standard EMF of a cell involving cell reaction Zn + 2Ag+ Zn++ + 2Ag Given :

zn/zn++ = 0.76V ; E°Ag/Ag+ = –0.80V

Q23. Give two differences between metallic and electrolytic conductors.

Q24. What is a weak electrolyte ?

Q25. Calculate EoMF of the following cell:

Cu | Cu2+ || Ag+ | Ag

Given is E° Cu2+ | Cu = +0.34V

Eo Ag / A g+ =-.80 V

Q26. While giving labelled diagram of dry cell write reactions taking place at cathode and anode.

Q27. Name two metals which are extracted electrolytically.

Q28. ∧°m for NaCl, HCl and NaAc are 126.4, 425.9 and 91.05 cm² mol-1 respectively. Calculate ∧° for HAc.

Q29. Rusting of iron is said to be an electrochemical phenomenon. Give reason for this.

Q30. Mercury cell gives a constant voltage of 1.35 V during its life time. Why?

Q31. What is strong electrolyte ?

Q32. Chemical reaction Zn → Zn2+ + 2e is an example of ____________ process.

Q33. Write units of specific conductance.

Ans – siemens per meter ( Sm–1)

Q34. How much charge required in Coulomb for the following reductions or oxidations ? Most Important

  • 1 mole of Al3+ to Al
  • 1 mole of H2O to O2
  • 1 mole of MnO4 to Mn2+
  • 1 mole of Cu2+ to Cu
  • 1 mole FeO to Fe2O3
  • 1 mole of MnO42- to MnO2
  • 1 mole of Pb4+ to Pb2+
  • 1 mole of CaCl2 to Ca
  • 1 mole of MnO4 to MnO2
  • 1 mole of Fe3+ to Fe2+ 
  • 1 mole of ZnO to Zn
  • 1 mole of CrO3 to Cr3+

Q35. What is electrochemical series ? Give its three applications. Most Important


HBSE Class 12 Chemistry Chapter 3 – Chemical Kinetics Important Questions 2024

Q1. Define the following terms: (a) Half life time (b) Order of a reaction

Q2. Define half life period and rate of reaction. Most Important

Q3. Calculate the half life of a first order reaction from rate constant 200 sec-1. Most Important

Q4. Define the terms: (i) Molecularity (ii) Rate constant

Q5. Explain the importance of Activation Energy.

Q6. What is Activation Energy? Most Important

Q7. Define Catalyst and Activation Energy.

Q8. A catalyst __________  the activation Energy.

Q9. The rate constant for a first order reaction is 60 S-1. How much time will it take to reduce the initial concentration of the reactant to its  \displaystyle \frac{1}{{16}}th value ?

Q10. A first order reaction has a rate constant 1.15 x 10-3 S-1 . How long will 5 g of this reactant take to reduce to 3 g? Most Important

Q11. The rate constants of a reaction at 500 K and 700 K are 0.02 S-1 and 0.07 S-1 respectively. Calculate the value of Ea.

Q12. The decomposition of NH3 on Platinum surface is zero order reaction. What are the rate of production of N2 and H2 if K = 2.5 x 10-4 mol-1 L-1 S-1 ?

Q13. For a first order reaction, show that time required for 99% completion is twice the time required for completion of 90% of the reaction.

Q14. A first order reaction takes 40 min. for 30% decomposition. Calculate half-life period.

Q15. Derive the integrated rate equation for first order reaction.

Q16. Under what condition a bimolecular reaction behaves kinetically first order reaction?

Q17. Define collision frequency. Most Important

Ans – The number of collisions per second per unit volume of the reaction mixture is known as collision frequency (Z).

Q18. Define Molecularity of a reaction and collision frequency.

Q19. The sum of the powers of the concentration of the reactants in rate law called ___________.

Ans – the order of that chemical reaction

Q20. What do you mean by molecularity of a reaction and order of at reaction ?

Q21. Identify the reaction order from the following rate constant: 1 k = 3.5×10-5 L mol-1s-1

Q22. What are complex reactions?

Ans – When a sequence of elementary reactions (called mechanism) gives us the products, the reactions are called complex reactions.

Q23. “A balanced chemical equation never gives us a true picture of how a reaction takes place.” Justify the statement by taking a suitable example.

Q24. What are Elementary reactions?

Ans – A balanced chemical equation never gives us a true picture of how a reaction takes place since rarely a reaction gets completed in one step. The reactions taking place in one step are called elementary reactions.

Q25. Rate of reaction controlled by slowest step called __________

Ans – rate determining step

Q26. Is it possible that Molecularity of a reaction can be zero?

Q27. If K = 0.693/t1/2 the order of reaction will be __________ .

Ans – first order reaction

Q28. What is effect of temperature on rate of a reaction?

Q29. In the equation K = Ae-Ea/RT is ____________.

Ans – -18230.8

Q30. Define order of reaction and instantaneous rate of reaction.

HBSE Class 12 Chemistry Chapter 4 – The d and F block Elements Important Questions 2024

Q1. What are transition elements? Write the electronic configuration of Cr(24) & Cu(29).

Q2. Why transition elements show variable oxidation state ?

Q3. Silver atom has completely filled ‘d’ orbitals (4d10) in its ground state. How can you say that it is a transition element ?

Q4. The general electronic configuration of inner transition elements is _____________.

Q5. The general electronic configuration of transition element is __________

Q6. Why do transition elements exhibit tendency for complex formation ? Explain with example. Most Important

Q7. Write a note on lanthanide contraction.

Q8. What is Lanthanide contraction ? Explain its reasons and consequences. Most Important

Q9. What is meant by Lanthanoid Contraction and write down its two consequences?

Q10. Explain giving reasons:

(i) The highest oxidation state is exhibited in oxoanions of a transition metal.

(ii) The E° (M2+/M) value for copper is positive (0.34 V).

Q11. Define Diamagnetic and Ferromagnetic substance.

Q12. Calculate the Magnetic moment of a divalent ion in aqueous solution with atomic number 25.

Q13. Explain why Cu+ ion is not stable in aqueous solution.

Q14. Write the electronic configuration of:

(i) Co2+ (27) (ii) Ce4+ (58) (iii) Lu2+ (71) (iv) Pm3+ (v) Fe2+ (vi) Cr (vii) Mn2+

Q15. Compare the chemistry of the actinoids with that of lanthanoids with reference to:

(a) Electronic configuration

(b) Oxidation states

(c) Chemical reactivity

Q16. Name the members of the lanthanoid series which exhibit +4 oxidation states and those which exhibit +2 oxidation states. Try to correlate this type of behaviour with the electronic configurations of these elements.

Q17. Why are Mn2+ compounds more stable than Fe2+ towards oxidation to their +3 state.

Q18. What are different oxidation states exhibited by the lanthanoids ?

Q19. Why transition metals and many of their compounds show paramagnetic behaviour ?

Q20. The transition metals generally form coloured compounds. Give reasons. Most Important

Q21. Describe the oxidising action of K2Cr2O7 and the ionic equations for its reaction with: (a) iodide ion (b) iron (II) solution (c) H2S. Most Important

Q22. Describe the preparation of potassium permanganate. How does acidified KMnO4 solution react with : (i) SO2 (ii) Oxalic acid (iii) FeSO4  , Write ionic equations for these reactions.

Q23. Compare the chemistry of actinoids with that of lanthanoids with special reference to: (i) Atomic sizes (ii) Chemical reactivity

Q24. Which metal in the first series of transition metals exhibits +1 oxidation state most frequently and why?

Q25. Describe the preparation of KMnO4 from Pyrolusite ore.

Q26. Discuss briefly the following properties of transition metals: (i) lonic radii (ii) Complexing tendency (iii) Catalytic properties

Q27. Explain the magnetic behavior of transition metals.

Q28. What is paramagnetism? Give one example.

Q29. How would you account for the following?

(i) Transition metals acts as good catalysts.

(ii) Transition metal forms coloured compounds.

Q30. What are interstitial compounds? Why are such compounds well-known for transition metals ?

Q31. Transition Metals are form Interstitial compounds Explain. Most Important

Q32. Explain giving reasons transition metals and their many compounds act as good catalyst. Most Important

Q33. Zn, Cd and Hg metals are not considered as transition metals. Give reason.

Q34. Explain the following with reference to Transition metals :

(i) Oxidation states

(ii) Catalytic properties

Q35. How is variability in oxidation states of transition metals different from that of the non-transition metals? Illustrate with examples.

Q36. Why the enthalpies of atomization of the transition metals are high ?

Q37. What is inert pair effect?

Q38. Write note on interstitial compounds.

Q39. Account for the following: Actinoids has greater tendency to form complexes in comparison to Lanthanoids.

Q40. Which form of sulphur shows paramagnetic behaviour?

Q41. Explain giving reason:

(i) Transition metal and many of their compounds show paramagnetic behaviour. Most Important

(ii) The enthalpy of atomization of the transition metal are high.

(iii) The transition metal generally forms coloured compounds.

(iv) Transition metal acts as good catalyst..

(v) Draw the structure of MnO4 Ion.

Q41. Discuss five uses of d and f-block elements.

Q42. Describe the Haber process for manufacture of ammonia.

Q43. Describe the reactivity of actinoids.

Q44. Members of second and third transition series exhibit similar atomic radii. Explain.

Q45. What are alloys ? Give two examples.

Q46. Prepare Potassium Permanganate from Pyrolusite ore.

Q47. Calculate Magnetic moment of a divalent ion whose atomic number is 27.

HBSE Class 12 Chemistry Chapter 5 – Coordination Compounds Important Questions 2024

Q1. Draw the diagram to show splitting of d-orbital in an octahedral crystal field.
Explain the splitting of ‘d’ orbitals in octahedral crystal field.

Q2. What is co-ordination number? What will be the co-ordination number of Pt in [PtCl6]-2 ?

Q3. What are ambidentate ligands ? Most Important

Q4. Explain Co-ordination isomerism with example. Most Important

Q5. Among Cl, OH, CO and NO2 only ____________ is Ambidentate Ligand.

Q6. What is meant by unidentate, didentate and ambidentate ligand? Give an example of each.

Q7. Write IUPAC names of following:

(1) [Co(NH3)6]ClMost Important

(2) [Co(NH3)5Br]SOMost Important

(3) [Pt(H2O)2BrNO2]

(4) [Ni(CO)4]

(5) K3[Fe(CN)6] Most Important

(6) K3[Fe(C2O4)3] Most Important

(7) K3[Al(C2O4)3Most Important

(8) K3[Cr(C2O4)3] Most Important

(9) [Cr(NH3)3(H2O)3]Cl3

(10) Zn2[Fe(CN)6]

(11) [Pt(NH3)4NO2Cl]SO4

(12) [Co(NH3)4Cl(NO2)]CI

(13) K4[Mn(CN)6]

(14) (p)O2N-C6H4-OCH3

Ans –

(1) [Co(NH3)6]Cl3 → Hexaamminecobalt(III) chloride

(2) [Co(NH3)5Br]SO4 → Pentammine bromo cobalt (III) sulphate

(3) [Pt(H2O)2BrNO2] → Diammineaquabromonitrito-O-platinum(II)

(4) [Ni(CO)4] → Tetracarbonylnickel(0)

(5) K3[Fe(CN)6] → potassium hexacyanoferrate(III)

(6) K3[Fe(C2O4)3] → Potassium trioxalatoferrate(III)

(7) K3[Al(C2O4)3] → Potassium trioxalatoaluminate(III)

(8) K3[Cr(C2O4)3] → Potassium trioxalatochromate(III)

(9) [Cr(NH3)3(H2O)3]Cl3 → Tris(ammine)triaquachromium(III) chloride

(10) Zn2[Fe(CN)6] → zinc hexacyanoferrate(II)

(11) [Pt(NH3)4NO2Cl]SO4 → Tetraamminechloronitritoplatinum(II) sulfate

(12) [Co(NH3)4Cl(NO2)]CI → Tetraamminechloridonitrocobalt(III) chloride

(13) K4[Mn(CN)6] → potassium hexacyanomanganate(II)

(14) (p)O2N-C6H4-OCH3 → 4-methoxy-1-nitrobenzene

Q8. Explain why [Fe(H2O)6]3+ is strongly paramagnetic whereas [Fe(CN)6]3- is weakly paramagnetic ?

Q9. Explain [Co(NH3)6]3+ is an inner orbital complex whereas [Ni(NH3)6]2+ is an outer orbital complex.

Q10. The hexaquamanganese (II) ion contains five unpaired electrons, while the hexacynoion contains only one unpaired electron. Explain using Crystal Field Theory.

Q11. Draw structures of optical isomers of [Co(NH3)Cl(en)2]2+

Q12. Explain why [Ni(CO)4] is paramagnetic while [NiCl4]2- is diamagnetic though both are tetrahedral?

Q13. Explain why a solution of [Ni(H2O)6]2+ is green but a solution of [Ni(CN)4]2- is colourless ?

Q14. [Fe(CN)6]4- and [Fe(H2O)6]2+ are of different colours in dilute solution. Why?

Q15. What is meant by Chelate complex.

Q16. Define chelate with example. Write the importance of chelate.

Q17. What is optical isomerism? Explain with one example.

Q18. What are ligands?

Ans – The ions or molecules bound to the central atom/ion in the coordination entity are called ligands

Q19. ____________ type of isomerism is present in [Cr(H2O)5CN]Cl2 and [Cr(H2O)5NC]Cl2

Ans – Solvate

Q20. Explain polydentate and bidentate ligands with example.

HBSE Class 12 Chemistry Chapter 6 – Haloalkanes and Haloarenes Important Questions 2024

Q1. What are antibiotics ? Give two examples.

Q2. What are ambident nucleophiles ? Explain with an example. Most Important

Q3. Among the isomeric alkanes of C5H12 identify the one that on photochemical chlorination yields :  (i) A single monochloride (ii) Three isomeric monochlorides  (iii) Four isomeric monochlorides

Q4. Explain why: (a) Alkyl halides, though polar, are immiscible with water? (b) Grignard reagent should be prepared under anhydrous conditions ?

Q5. Explain with example Friedel-Crafts alkylation of Methoxybenzene. Most Important

Q6. Write the following reactions: (a) Swarts reaction (b) Sandmeyer reaction (c) Wurtz-fitting reaction

Q7. What is Wurtz reaction? Most Important

Ans –Alkyl halides react with sodium in dry ether to give hydrocarbons containing double the number of carbon atoms present in the halide. This reaction is known as Wurtz reaction.

2RX + 2Na RR + 2NaX

Q8. Write chemical equation for a Wurtz reaction.

Ans – 2RX + 2Na RR + 2NaX

Q9. Give the uses of:  (a) Freon (b) D.D.T. (c) Tetrachloromethane

Q10. Explain the mechanism of SN2 reaction.

Q11. How would you differentiates between SN1 and SN2 Mechanisms of substitutions reactions? Give one example of each.

Q12. Predict the order of reactivity of the four isomeric bromobutanes in SN1 and SN2 reaction.

Q13. In the following pairs of halogen compound which would undergo SN2 reaction faster ?


Among CH3CH2CH2CH2I and CH3CH2CH2CH2Cl will show SN2 reaction fast.

Ans –

(i) (a) is primary halide and therefore undergoes SN2 reaction faster.

(ii) (a) As iodine is a better leaving group because of its large size, it will be released at a faster rate in the presence of incoming nucleophile.

Q14. In the following pairs of halogen compounds which compound undergoes faster SN1 reaction?



Q15. What is dehydrohalogenation reaction?

Q16. Discuss the nature of C-X bond in halogens.

Q17. What happens, when :

(A) Ethyl Chloride is treated with aqueous KOH

(B) Methyl bromide is treated with Na in presence of dry ether.

(C) Methyl Chloride is treated with KCN.

Q18. Convert Propanone to Propene. Most Important

Q19. Convert Ethanol to 3- Hydroxybutanal.

Q20. Give an example of β-elimination reaction of alkyl halides.

Q21. How will you bring about following conversions?

(a) Toluene to Benzyl alcohol.

(b) But-1-ene to But-2-ene.

(c) Tert-Butyl bromide to Isobutyl bromide.

Q22. What happens when :

(i) n-butyl chloride is treated with alcoholic KOH?

(ii) Bromobenzene is treated with Mg in the presence of dry ether?

(iii) Ethylbromide is treated with Na in the presence of dry ether?

Q23. What is SN1 reaction? Explain with example.

HBSE Class 12 Chemistry Chapter 7 – Alcohols, Phenols and Ethers Important Questions 2024

Q1. Write the IUPAC names of following compounds:


(2) C6H5–O–C6H5

(3) C6H5CH2CH2Cl →

(4) (CH3CH2)2NCH


(6) Most Important


Q2. Although chlorine is an electron withdrawing group, yet it is ortho-para directing in electro- philic aromatic substitution reactions, why ?

Q3. Write short note on: (a) Williamson Ether Synthesis (b) Kolbe’s Reaction (c) Unsymmetrical ether.

Q4. Explain with example Kolbe’s reaction. Most Important

Q5. Explain with example Reimer-Tiemann reaction. Most Important

Q6. Predict the major product of acid catalysed dehydration of 1-methylcyclohexanol.

Q7. Explain why propanol has higher boiling point then the hydrocarbon.

Q8. What is meant by Hydroboration-oxidation reaction? Illustrate it with an example.

Q9. Write the Mechanism of hydration of ethene to yield ethanol.
Write the three steps mechanism of hydration of ethene to yield ethanol.

Q10. Discuss the acidic nature of phenols.

Q11. Give the equation of the following reaction: (i) Bromine in CS2 with phenol. (ii) Dilute HNO3 with phenol.

Q12. How would you convert the following: (i) Propene to propan-2-ol (ii) Benzyl Chloride to Benzyl alcohol.

Q13. Write the mechanism of acid dehydration of ethanol to yield ethene. Most Important

Q14. Name the reagent used in Oxidation of a primary alcohol to carboxylic acid.

Q15. Name the reagent used in Oxidation of a primary alcohol to aldehyde.

Q16. Give reason for the higher boiling point of ethanol in comparison to methoxymethane ?

Q17. Write the mechanism of the reaction of HI with Methoxymethane.

Q18. Name any two tests to distinguish Alcohol from Phenol.

Q19. p-Nitrophenol is more acidic than phenol explain why ?

Q20. What are primary, secondary and tertiary alcohols ?

Q21. Write acidic order of Primary, Secondary and Tertiary alcohols.

Q22. Give a chemical test to distinguish between Phenol and Benzoic acid.

Q23. Phenol is more acidic than Ethanol, explain.

Q24. Write the equations for the reaction of Phenol with the following: (i) Bromine (Br2) water (ii) Zinc

Q25. Give mechanism for following reaction:

Q26. CH3CH2OH  \displaystyle \xrightarrow[{443k}]{{{{H}<em>{2}}S{{O}</em>{4}}}} Most Important

Q27. What is Denatured alcohol ?

Ans – drink ethanol mixed with methanol called denatured alcohol.

Q28. Why Phenol is more Acidic then Alcohol ?
Why alcohol is less acidic then phenol?

Q29. Name the reagent used in dehydration of Ethanol into Ethene.

Q30. Explain with example Williamson Ether Synthesis.

Q31. Why ortho-nitrophenol and para-nitrophenol are more acidic then phenol ? Draw the resonance structure of phenoxide ions.

Q32. Explain why ortho-nitrophenol is more acidic then ortho-methoxyphenol.

HBSE Class 12 Chemistry Chapter 8 – Aldehydes, Ketones and Carboxylic Acids Important Questions 2024

Q1. Write the IUPAC names of following compounds:

(1) CH3CH–(CH3)–CHO →

(2) C6H5–CH2–CHO →


(4) C6H5CH = CHCHO →

(5) CH3-CH=CHCHO →

(6) CH3CH(CH3)CH2CHO →

(7) (CH3)3CCH2COOH →


(9) CH3–CH2Br–COOH →

(10) COOH–CH2–CH2–COOH →

Q2. Describe Aldol condensation reaction. Most Important

Q3. Describe Cross Aldol Condensation reaction. Most Important

Q4. Describe Decarboxylation reaction.  Most Important

Q5. Describe the following: (i) Hell-Volhard-Zelinsky Reaction (ii) Cannizzaro reaction (iii) Rosenmund reduction (iv) Stephen reaction (v) Clemmensen reduction (vi) Wolff-Kishner reduction (vii) Esterification Most Important

Q6. What is meant by following term’s, give an example of the reaction in each case?

(i) Cynohydrin

(ii) 2, 4, D.N.P.

(iii) Kolbe’s Electrolysis

(iv) Hemi-acetal

(v) Ketal

Q7. Describe Decarboxylation.

Q8. How will you prepare Aldehyde from (i) Alcohol (ii) (RCOO)2–Ca (iii) Alkyne

Q9. Why Aldehyde undergo nucleophilic addition reactions more readily than ketones? Explain.

Q10. Why carboxylic acids do not give characteristic reactions of Carbonyl group ?

Q11. Give two methods of preparation of Ketones and write the chemical reactions.

Q12. What is Cannizaro’s reaction ? Write its mechanism ? Most Important

Ans – 

Q13. Discuss the structure of Carbonyl group.

Q14. What is Hell Vohlard Zelinsky reaction?

Q15. Give two important uses of carboxylic acids.

Q16. How will you prepare R-COOH from?

(i) Alcohol

(ii) Nitrile

Q17. Draw structure of 4-Oxopentanal.

Q18. Convert Benzene into : Most Important

(i) Acetophenone

(ii) Benzaldehyde

(iii) Benzophenone

Q19. Compare the acidic strength of following acids :  (i) CH3COOH (ii) HCOOH (iii) C6H5COOH

Q20. Draw structure of cyclopropanone oxime.

Q21. How will you bring about following conversions ?
(i) Benzoic acid to m-Nitrobenzyl alcohol.
(ii) Benzaldehyde to Benzophenone
(iii) Benzoic acid to Benzamide.

Q22. Give a simple chemical test to distinguish between benzaldehyde and acetophenone.

Q23. Out of benzoic acid and phenylacetic acid, which is stronger acid and why ?

Q24. An organic compound ‘A’ (molecular formula C8H16O2) was hydrolysed with dil. H2SO4 to give a carboxylic acid ‘B’ and an alcohol ‘C’. Oxidation of ‘C’ with chromic acid produced ‘B’. ‘C’ on dehydration gives but-1-ene. Write equations for the reactions involved.

Q25. Cyclohexanone forms cynohydrin in good yield but 2, 2, 6-trimethylcyclohexanone does not. Explain.

Q26. Explain the mechanism of nucleophilic addition reactions of aldehydes and ketones.

Q27. Give mechanism for the nucleophilic addition reaction of HCN with propanone.

Q28. Describe the effect of substituents on the acidity of carboxylic acids.

Q29. Draw structure of 3-Hydroxybutanal.

Q30. Tollen’s reagent is  __________.

Ans – Ammoniacal silver nitrate solution

Q31. Convert Ethanal into following: (i) Ethanal to Butane 1,3-diol (ii) Ethanal to But 2-enal (iii) Ethanal to But-2 enoic acid

Q32. Convert Ethanal to But-2-enal.

Q33. Write the products of the following reactions: Most Important



HBSE Class 12 Chemistry Chapter 9 – Amines Important Questions 2024

Q1. Aliphatic amines stronger base than aromatic amines, explain.

Q2. What are crystalline solids ? Give two examples.

Q3. Write down the Gattermann reaction, and why this reaction preferred over Sandmeyer reaction ?

Q4. Give chemical equations for the following reactions:

(i) Gatterman Reaction

(iii) Ammonolysis

Q5. Write a short note on carbylamine reaction. Most Important

Q6. Aromatic primary amines cannot be prepared by Gabriel phthalamide reaction. Explain.

Q7. What is Hoffmann bromamide degradation reaction?

Q8. Arrange the following in decreasing order of their basic strength: C6H5NH2, C2H5NH2, (C2H5)2NH, NH3

Ans –The decreasing order of basic strength of the above amines and ammonia follows the following order: (C2H5)2NH > C2H5NH2 > NH3 > C6H5NH2

Q9. Why Diazonium salts of aromatic amines are more stable than aliphatic amines ?

Q10. What is Diazotisation reaction?

Q11. Primary, Secondary and Tertiary amines differentiated by ____________.

Q12. Give one chemical test to distinguish between secondary and tertiary amines.

Q13. Distinguish between Aniline and Benzylamine with the help of a chemical test.

Q14. Give one chemical test to distinguish between aniline and N-methylaniline.

Q15. Why ethylamine is soluble in water whereas aniline is not ?

Q16. Although amino group is o- and p-directing in aromatic electrophilic substitution reactions, aniline on nitration gives a substantial amount of m-nitroaniline. Give reason.

Q17. Why Aniline does not undergo Friedel-Crafts reaction ?

Q17. What is Gabriel Phthalimide synthesis reaction? Most Important

Q18. Why Gabriel phthalimide synthesis is preferred for synthesizing primary amines?

Q19. Write short note on Hofmann’s bromamide degradation reaction. Most Important

Q20. Write a short note on Hofmann’s bromamide reaction. Most Important

Q21. Write a short note on coupling reaction. Most Important

Q22. Describe Acetylation.

Q23. How will you convert benzene to m-Bromophenol ?

Q24. What is carbylamines test for 1° amine ?

Q25. Write the increasing of strongest basicity of the following:

C2H5NH2 , C6H5NH2 , (C2H5)2NH and C6H5CH2NH2

Q26. How will you convert aniline into the following? (a)  p-bromoaniline (b)  p-hydroxyazobenzene

HBSE Class 12 Chemistry Chapter 10 – Biomolecules Important Questions 2024

Q1. What is the basic structural difference between starch and cellulose ?

Q2. What is glycogen? How is it different from starch ?

Q3. What are the expected products of hydrolysis of lactose ?

Q4. What are the expected products of hydrolysis of Sucrose ?

Q5. Write differences between fibrous and globular proteins.

Q6. What are vitamins ? Name any two vitamins.

Q7. Why vitamin A and C are essential to us ? Name one important source of each.

Q8. Deficiency of Vitamin ‘C’ causes ___________.

Q9. ____________ is the deficiency disease of Vitamin ‘D’.

Q10. Deficiency of Vitamin ‘A’ causes __________

Q11. Name the disease caused by deficiency of Vitamin K.

Q12. Write the names of two vitamins soluble in fats. Most Important

Q13. Deficiency of Vitamin ‘B1‘ causes __________

Q14. Define the terms :
(i) Biomolecules
(ii) Carbohydrates
(iii) Reducing Sugars Most Important

Q15. What are hydrolysis products of lactose ?

Q16. What are glycosidic and peptide linkage ?

Q17. What are essential and non-essential amino acids ? Give one example of each type. Most Important

Q18. What do you mean by denaturation of a protein? How does it affect properties of protein ?

Q19. Write short note on denaturation of proteins.

Q20. What are two main functions of Nucleic Acids ?

Q21. Define the following terms:

(a) Anomer

(b) Peptide Bond OR Peptide linkage Most Important

(c) Reducing sugar

Q22. What is essentially the difference between ∝-glucose and β-glucose? What is meant by pyranose structure of glucose ?

Q23. Define coagulation.

Q24. Write four differences between DNA and RNA. Most Important

Q25. What type of linkage is there in Amylopectin?

Ans – C1–C4 glycosidic linkage

Q26. What are Non-reducing sugars ?

Ans – In disaccharides, if the reducing groups of monosaccharides i.e., aldehydic or ketonic groups are bonded, these are non-reducing sugars, e.g., sucrose. On the other hand, sugars in which these functional groups are free, are called reducing sugars, for example, maltose and lactose.

Q27. How many bases are present in DNA and RNA each ?

Q28. In RNA, the four basis present are Adenine, Guanine, Cytosine and __________.

Ans – thymine


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