Chemistry | Grade 12-XII | Impotent Question & Answer 2078

class 12 chemistry importent question
Lab preparation of :
  • Chloroform (trichloromethane )
  • Diethyl ether (Ethoxy ethane)
  • Formic acid (methanoic acid)
  • Nitrobenzene
  • Aniline
Separation process :
  • Identification of 1º, 2º, and 3° alcohols by Victor Meyer's method.
  • Separation of 1, 2°, and 3° amines by Hoffmann's method.
Name reactions :
  • Aldol condensation
  • Cannizaro's reaction
  • Perkins condensation
  • Claisen Condensation reaction.
  • Benzoin condensation
  • Carbylamine reaction (Oxo process)
  • Reimer Tiemann reaction
  • Coupling reaction( preparation of azo dyes)
  • Diazotization reaction
  • Friedel- Craft's reaction
  • Hoffmann's Bromamide reaction, Decarbonylation reaction
  • Esterification reaction
  • Carbonylation reaction
  • Williamson's etherification reaction
  • Rosenmund reduction
Test reactions :
  • Iodoform test ( NaOH + I2)
  • Fehling's test ( alkaline solution of copper sulfate)
  • Silver mirror test( reaction with Tollens reagent)
  • The nitrous acid test of 1º, 2º, and 3° amines.
  • 2,4 – DNP test
  • Carblyamine test ( test of primary amines)
Important reactions :
  • Reduction of nitrobenzene in a different mediums.
  • Preparation of alcohol using a Grignard reagent. C3H8 and C4H10
  • Oxidation of alcohols. ( 1, 2 & 3 degree)
  • Fermentation
  • All reactions of chloroform.
Reactions to prepare :
  • DDT
  • Picric acid
  • BHC
  • Urotropin
  • Chloropicrin
  • TNT
Convertion :
  • 1-bromopropane to 2- bromopropane and vice versa.
  • propane-1-ol to propane-2-ol and vice versa.
  • Methenamine to ethanamine and vice versa.
  • Phenol to anisole(methoxy benzene) and vice versa.
  • Ethoxy ethane to methoxy ethane.
  • Phenol/aniline to azo-dye.
  • Ethanal/ ethanol to 3-hydroxy butanal.
  • Ethanol to 2-hydroxyl propanoic acid.
  • Propanone(acetone) to 2-hydroxy-2-methyl propanoic acid.
  • Phenol to toluene.
  • Ethanol to propanol/ propanoic acid.
  • Methanamide to ethanamine.
Short questions of Organic Chemistry
  • Why is chloroform stored in a dark bottle containing ethanol?
  • Why does chloroform not give white ppt with aq AgNO3?
  • Why is nucleophilic substitution reaction difficult in haloarene?
  • Why is the boiling point of ethanol greater than that of ethoxy ethane?
  • Why is phenol more acidic than aliphatic alcohol?
  • Why does nitrobenzene undergo an electrophilic substitution reaction at meta position? (Explain why -NO2 group is meta directing towards electrophilic aromatic substitution)
  • Why is chlorobenzene o/p - directing towards electrophilic substitution reaction?
  • It is dangerous to boil a sample of ether stored for a long time, give a reason.
  • Ether is stored in a bottle containing iron wire, why?
  • Give a suitable test to distinguish ethanamine from N-methyl methenamine.
  • Write a chemical test to distinguish ethanoic acid(acetic acid) from methanoic acid(formic acid).
  • Why is a chloroacetic acid stronger acid than acetic acid?
  • Why is a formic acid stronger acid than acetic acid?
  • Why an amino group of aniline is protected before nitration?(Aniline can not be nitrated directly, why?)
  • Write the functional isomers of C3H80 with their IUPAC name. Give a chemical test to distinguish them.
  • Write an unsymmetrical ether of C3H8O. How would you prepare this ether using Williamson's synthesis?
  • Write down possible isomeric amines of C3H9N and give their IUPAC names.
  • What is a peptide bond(linkage)? Write an example of the dipeptide.
  • What are disaccharides? What happens when a disaccharide is hydrolyzed.
  • Define protein. What is meant by denaturation of protein?
  • What is soap? How is soap obtained from fat? (What is saponification?)(What happens when a fat/oil is hydrolyzed?)
  • Write monomers and one use of:
    • Bakelite
    • Nylon-6,6
    • polyvinyl chloride(PVC)
    • Teflon
The structural formula and one use
  • Analgesic drug antipyretic drug
  • Antibiotics Antiseptics
  • Herbicide Pesticide
  • Germicide Insecticide
  • A synthetic fertilizer – nitrogen fertilizer/Phosphorus (phosphatic) fertilizer, mixed(NPK) fertilizer.
What happens when
  • Sodium benzoate is heated with soda lime.
  • Phenol is heated with zinc dust.
  • Chlorobenzene is treated with chloral.
  • Ethyl alcohol(ethanol) is treated with acetic acid(ethanoic acid)
  • Phenol is treaded with aq. Br
  • Aniline is treated with aq. Br
  • Phenol is treated with benzene diazonium chloride.
  • Ethoxy ethane is treated with HI.
  • Methanal(formaldehyde) is treated with ammonia.
  • Methanal/benzaldehyde is treated with NaOH.
  • Ethanal/propanone is treated with NaOH.
  • Aldehyde/ketone is treated with hydroxylamine.
  • Ethanol is heated with conc. H2SO
  • Acetic acid is treated with P205
5 Marks questions
  • Selection of indicators.
  • Different concepts of acids and bases and their limitations
  • Common ion effect and solubility product principle and its application.
  • Faraday's laws of electrolysis.
  • Hess law.
  • Prediction of feasibility/ spontaneity of reactions in terms of free energy change and entropy change.
  • Differences between order and molecularity of a reaction.
  • Collision theory of reaction rate.
  • Factors affecting rate of reaction.
Short questions
1. Write hybridization of central atom and geometry of:
  • Ethene(ethylene)
  • ethane Ethyne (acetylene)
  • NH3
  • BF3
  • H20
  • H2S
2. Write any two features and an example of sp3/sp2/sp hybridization.
3. Define the terms:
  • Normality
  • Normality factor
  • Endpoint
  • Equivalent point
  • Titration error Seminormal solution
  • Decinormal solution
  • Indicator
  • Basicity of acid
  • Acidity of base
  • Standard solution(primary and secondary) with example.
4. What are primary standard substances? What are the requisites for a substance to be the primary standard?
5. Define molarity and normality. Write their Relationship.
6. What happens when HCl is passed through a saturated solution of NaOH?
7. Predict whether the aqueous solution of CuSO4/CaCl2/Na2CO3/NaCl is acidic basic or neutral. Give reason.
8. State Ostwald's dilution law. What is the limitation of this law?
9. Define pH and poH. Write their relation.
10. Define the terms:
  • Electrochemical equivalent (ECE).
  • Standard electrode potential.
  • One Faraday
11. Mention one important application of standard hydrogen electrode giving example.
12. State the first law of thermodynamics and point out its limitation.
13. Distinguish between an intensive and extensive property with one example of each.
14. Define enthalpy of combustion and enthalpy of formation.
15. Draw an energy profile diagram for exothermic and endothermic reactions.
16. Draw an energy profile diagram for catalyzed and uncatalyzed reactions.(How does catalyst increases the rate of reaction?)
17. State second law of thermodynamics. Explain this law on the basis of entropy change.
18. What is meant by the effective collision of reacting species? What are the essential conditions for the effective collision of reacting species?
19. Find the unit of rate constant of zero, first, second and third-order reaction.
SET A: Extraction of:
  • (Blister) copper from copper pyrites.
  • Steel ( Open Hearth and Bessemerization process)
  • Iron from iron pyrites.
Chemistry of
  • Blue vitriol ( CuSO4.5H20)
  • White vitriol ( ZnSO4.7H20)
  • Zinc white ( Zno)
  • Calomel (Hg2Cl2)
  • Corrosive sublimate (HgCl2)
  • Rusting of iron
Short questions
1. Copper metal becomes black/green when exposed to air for a long time, why?
2. What happens when copper is treated with conc. HNO3?
3. What is the effect of heat on blue vitriol?
4. What is Rainman's green? How it is prepared? Write its one important use.
5. Write the molecular formula of Philosopher's wool. How it is prepared?
6. What is Nessler's reagent? How is it prepared? 7. What is the composition of stainless steel? Write its one use.
8. Distinguish between quenching and tempering of steel.
9. Rusting (corrosion) of iron and methods of prevention. — (5 marks too.)
10. Why does silver nitrate produces permanent black stain on the skin?
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