Class 12 Chemistry : Important Questions and Topics for NEB exam. - Note Library


Class 12 Chemistry : Important Questions and Topics for NEB exam.

Class 12 chemistry important questions

In this post, we will cover the most important chemistry questions and topics for the NEB (Board Exam).

Important Question of Class 12 Chemistry

Unit Volumetric Analysis

1.1 Define and explain the terms volumetric and gravimetric analysis.
1.2 Express the concentration of solutions in terms of percentage, g/l, molarity, molality, normality, ppm, ppb
1.3 Define and calculate the equivalent weight of (elements, acids, bases, salts, oxidising and reducing agents).
1.4 Express the concentration of solution in terms of normality.
1.5 Explain and apply the concept of law of equivalence in chemical calculation.
1.6 Define and explain primary and secondary standard substance.
1.7 Explain different types of titration and their applications.
(Things to study for exam)
⚫ define-end point, equivalence point, indicators, basicity of acid, acidimetry, normality, molarity. primary standard solution, secondary standard solution, alkalimetry, redox reaction, normality factor
⚫ requisites for a substance to be primary standard solution
⚫ what is the normality of 20 cc of 2M phosphoric acid (H3PO4)?
⚫How many moles of H.SO. are required to neutralize 4 liters of 2N NaOH solution? What mass of 90% pure CaCO, is required to neutralize @ liters of deci-normal solution of HCL?
⚫To convert molarity to G/L, normality, percentage.
⚫Numerical based on volumetric analysis

2. Ionic Equilibrium 
2.1 Explain the limitations of Arrhenius concepts of acids and bases.
2.2 Define Bronsted and Lowry concepts for acids and bases.
2.3 Define conjugate acids and conjugate base.
2.4 identify conjugate acid-base pairs of Bronsted acid and base.
2.5 Define and explain Lewis acids and bases.
2.6 Use the extent of ionization and dissociation constant of acid (ka) and base (kb). 
2.7 Explain ionization constant of water and calculate pH and pOH in aqueous medium using Kw values.
2.8 Show understanding of, and use, the concept of solubility product sp
2.9 Calculate Ksp from concentrations and vice versa.
2.10 Show understanding of the common ion effect.
2.11 Describe the application of solubility product principle and common ion effect in precipitation reactions.
2.12 Define a Buffer and show with equations how a Buffer system works.
 2.13 Explain the choice of suitable indicators for acid-base titrations and describe the changes in pH during acid-base titrations.
2.14 Define and differentiate different types of salts (simple salts, double salts, complex salt, acidic salts, basic salts and neutral salts).
2.15 Explain hydrolysis of salts (salts of strong acid and strong base, salts of weak acid and strong base and salts of weak base and strong acid).
(Things to study for exam)
⚫Numerical to find PH and P^OH, ⚫Numerical related to Ksp

3. Chemical Kinetics
3.1 Define chemical kinetics.
3.2 Explain and use the terms rate of reaction, rate equation, rate constant.
3.3 Explain qualitatively factors affecting rate of reaction. 
3.4 Use collision theory to explain how the rate of chemical reaction is influenced by temperature,concentration and particle size
3.5 Explain the meaning of the term activation energy and activated complex.
3.6 Derive and explain integrated rate equation and half life for zero, and first order reaction.
3.7 Construct and use rate equations calculating an initial rate using concentration data.
3.8 Explain the significance of Arrhenius equation and solve the related problems.
3.9 Explain and use the terms catalyst and catalysis (homogenous, heterogeneous).
3.10 Describe enzyme as biological catalyst.
3.11 Explain the role of catalyst in the reaction mechanism.
3.12 Solve related numerical problems based on rate, rate constant and order of zero and first order reactions.
(Things to study for exam)
⚫Define activation energy, half life, rate of a chemical run, energy profile diagram, effective collision,
⚫factor affecting rate of ran
⚫numerical related to rate of rxn

4. Thermodynamics
4.1 Define thermodynamics.
4.2 Explain the energy change in chemical reactions.
4.3 Define the terms internal energy and state function 
4.4 State and explain first law of thermodynamics.
4.5 State and explain enthalpy and enthalpy changes in various process (enthalpy of solution, enthalpy of formation enthalpy of combustion and enthalpy of reaction). 
4.6 Explain endothermic and exothermic process with the help of energy profile diagram.
4.7 State laws of thermo-chemistry and solve numerical problems related to Hess law.
4.8 Define the term entropy and spontaneity.
4.9 State and explain second law of thermodynamics.
4.10 Define standard Gibbs free energy change of see 4.11 Calculate AG for a reaction using the equn AG AH-TAS. ans of the equation AG=AH-TAS.
4.12 State whether a reaction or process will be spontaneous by using the sign of AG.
4.13 Explain the relationship between AG and equilibrium constant

5. Electrochemistry
5.1 Define the terms: standard electrode (redox) potential.
5.2 Explain about standard hydrogen electrode and calomel electrodes.
5.3 Calculate a standard cell potential by combining two standard electrode potential.
5.4 Describe the applications of electrochemical series.
5.5 Define and explain standard cell potential with reference to voltaic cell: Zn-Cu cell, Ag-Cu cell
5.6 Use standard cell potentials to: explain/deduce the direction of electron flow in a simple cell and predict the feasibility of a reaction.
5.7 Explain the relationship between cell potential and free energy change.
5.8 State the possible advantages of developing other types of cell, eg. the hydrogen/oxygen fuel cell and lithium-ion, rechargeable batteries.
(Things to study for exam)
⚫Define ECE (electrochemical equivalent), cell constant, molar conductivity, equivalent conductance,
electrolytic conduction, voltaic conduction, single electrode potential, standard hydrogen electrode.
Numerical based on anode cathode

6. Transition Metals
6.1 Explain characteristics of transition metals.
6.2 Explain oxidation states of transition metals
6.3 Describe complexions and metal complexes.
6:4 Show shapes of complexions.
6.5 Describe d-orbitals in complex ions (simple explanation by crystal field theory) for octahedral complex.
6.6 Explain reasons for the colour of transition metal compounds.
6.7 Explain catalytic properties of transition metals

7. Studies of Heavy Metals
7.1 Explain occurrence of heavy metals.
7.2 Describe extraction of heavy metals
7.3 Describe properties (with air, acids, aqueous ammonia and metal ions) and uses of copper.
7.4 Explain chemistry (preparation, properties and uses) of blue vitriol.
7.5 Write formula and uses red and black oxide of copper.
7.6 Describe properties (with air, acid, alkali, displacement reaction) and uses of zinc. 
7.7 Explain chemistry (preparation, properties and uses) of white vitriol.
7.8 State properties of mercury.
7.9 Explain chemistry (preparation, properties and uses) of calomel and corrosive sublimate
7.10 Explain properties and uses of iron.
7.11 Explain manufacture of steel by basic oxygen method and open hearth process. 7.12 Explain corrosion of iron and its prevention.
7.13 Explain preparation and uses of silver chloride and silver nitrate.

8. Haloalkanes
8.1 Describe briefly the nomenclature, isomerism and classification of monohaloalkanes
8.2 Show the preparation of monohaloalkanes from alkanes, alkenes and alcohols .
8.3 State physical properties of monohaloalkanes.
8.4 Describe chemical properties of haloalkanes: substitution reactions SN1 and SN2 reactions (basic concept only).
8.5 Show the formation of alcohol, nitrile, amine, ether, thioether, carbylamines, nitrite and nitro alkane using haloalkanes.
8.6 Describe elimination reaction (dehydrohalogenation Saytzeff's rule), Reduction reactions, Wurtz reaction.
8.7 Show the preparation of trichloromethane from ethanol and propanone. 
8.8 Explain the chemical properties of trichloromethane: oxidation, reduction, action on silver powder, conc. nitric acid, propanone, and aqueous alkali.

9. Haloarenes
9.1 Describe briefly the nomenclature and isomerism of haloarenes.
9.2 Show the preparation of chlorobenzene from benzene and benzene diazonium chloride.
9.3 State physical properties of haloarens.
9.4 Describe low reactivity of haloarenes as compared to haloalkanes in term of nucleophilic substitution reaction.
9.5 Explain the chemical propertiesof haloarens: reduction of chlorobenzene, electrophilic substitution reactions, action with Na (Fittig and Wurtz- Fittig reaction) and action with chloral.
9.6 Describe uses of haloarenes 

10. Alcohols
10.1 Describe briefly the nomenclature, isomerism and classification of monohydric alcohol.
10.2 Distinguish primary, secondary and tertiary alcohols by Victor Meyer's Method.
10.3 Show the preparation of monohydric alcohols from Haloalkane, primary amines and esters.
10.4 Explain the industrial preparation alcohol from: oxo process, hydroboration-oxidation of ethane & fermentation of sugar. 
10.5 Define absolute alcohol, power alcohol, denatured alcohol (methylated spirit), rectified spirit; and alcoholic beverage.
10.6 State physical properties monohydric alcohols.
10.7 Explain chemical properties of monohydric alcohols with HX, PX3, PCIS, and SOCIZ. Action with reactive metals like Na, K and Li, Dehydration of alcohols. Oxidation of primary, secondary and tertiary alcohol with mild oxidizing agents like acidified KMnO4 or K2Cr207. Catalytic dehydrogenation of 1°
and 2° alcohol and dehydration of 3 alcohol, Esterification reaction and test of ethanol.

11. Phenols
11.1 Describe briefly the nomenclature of phenol.
11.2 Show the preparation of phenol from chlorobenzene, Diazonium salt and benzene sulphonic acid
11.3 State physical properties of phenol.
11.4 Describe acidic nature of phenol (comparison with alcohol and water).
11.5 Explain the chemical properties of phenol with NH3, Zn, Na, benzene diazonium chloride and phthalic anhydride. Acylation reaction, Kolbe's reaction and Reimer-Tiemann's reaction Electrophilic substitution (nitration, sulphonation, brominaiton and Friedal Craft's alkylation).
11.6 Describe test of phenol (FeCl3 test, aq. Bromine test &Libermann test).
11.7 State important uses of phenol.

 12. Ethers
12.1 Describe briefly the nomenclature, classification and isomerism of ethers.

12.2 Show the preparation of aliphatic and aromatic ethers from Williamson's synthesis.
12.3 State physical properties of ether.
12.4 Explain chemical properties of ethoxyethane with HI, Conc. HCI, Conc. H2SO4, air and C12
12.5 State important uses of ethers

13. Aldehydes and Ketones
(A) Aliphatic aldehydes and ketones
13.1 Describe briefly the nomenclature and isomerism of aliphatic aldehydes and ketones.
13.2 Show the preparation of aldehydes and ketones from dehydrogenation, oxidation of alcohol,ozonolysis of alkenes, acid chloride, gem dihaloalkane and catalytic hydration of alkynes
13.3 State physical properties of aldehydes and ketones.
13.4 Describe structure and nature of carbonyl group.
13.5 Explain chemical properties of aliphatic aldehydes and ketones, ie addition of H2, HCN and NaHS03. action of aldehyde and ketone with ammonia derivatives, i.e. NH2OH, NH2-NH2, phenyl
hydrazine and semicarbazide. Aldol condensation, Cannizzaro's reaction, Clemmensen'sreduction and
Wolf Kishner reduction. Action with PCIS and action with LAIH4 Action of methanal with ammonia and phenol.
13.6 Distinguish between aliphatic aldehydes and ketones by using 2,4- DNP reagent, Tollen's reagent and Fehling's solution.
13.7 Define formalin and state its uses.

B) Aromatic aldehydes and ketones
13.8 Show the preparation of benzaldehyde from toluene and acetophenone from benzene.
13.9 Explain chemical properties of benzaldehyde, i.e. Perkin condensation, Benzoin condensation, Cannizzaro's reaction and electrophilic substitution reaction.

14. Carboxylic Acid and its Derivatives

(A) Aliphatic and aromatic carboxylic acids
14.1 Describe briefly the nomenclature and isomerism of aliphatic and aromatic carboxylic acids.
 14.2 Show the preparation of monocarboxylic acids from: aldehydes, nitriles, dicarboxylic acid, sodium alkoxide and trihaloalkanes.
14.3 Show the preparation of benzoic acid from alkyl benzene.
14.4 State physical properties of monocarboxylic acids.
14.5 Explain chemical properties of aliphatic and aromatic carboxylic acids: Action with alkalies, metal oxides, metal carbonates, metal bicarbonates, PC13, LIAIH4 and dehydration of carboxylic acid.Hell Volhard Zelinsky reaction. Electrophilic substitution reaction of benzoic acid (bromination,nitration and sulphonation).
14.6 Explain effect of constituents on the acidic strength of carboxylic acid.
14.7 Describe abnormal behaviour of methanoic acid.

(B) Derivatives of Carboxylic acids (acid halides, amides, esters and anhydrides)
14.8 Show the preparation of acid derivatives from carboxylic acid.
14.9 Explain the comparative physical properties of acid derivatives
14.10 Explain the comparative chemical properties of acid derivatives (hydrolysis, ammonolysis, amines RNH2), alcoholysis, and reduction only. Claisen condensation and hofmannbromamide reaction.
14.11 Describe amphoteric nature of amide and relative reactivity of acid derivatives reaction.

15. Nitro Compounds
15.1. Describe briefly the nomenclature and isomerism of nitro compounds
15.2 Show the preparation from haloalkane and alkane.
15.3 State physical properties of nitro compounds.
15.4 Explain chemical properties of nitro compounds, reduction.
15.5 Show preparation of nitrobenzene from benzene.
15.6 State physical properties of nitrobenzene.
15.7 Explain chemical properties of nitrobenzene, Le. reduction in different media and electrophilic substitution reactions (nitration, sulphonation & bromination).
15.8 State important uses of nitro compounds.

16. Amines
(A) Aliphatic amines
16.1 Describe briefly the nomenclature, classification and isomerism of amines.
16.2 Show the separation of primary, secondary and tertiary amines by Hoffmann's method.
16.3 Show preparation of primary amines from haloalkane, nitriles, nitroalkanes and amides.
16.4 State physical properties of aliphatic amines.
16.5 Explain chemical properties of aliphatic amines, l.e. basicity of amines, comparative study ofbasic nature of 1°, 2° and 3° amines. Reaction of primary amines with chloroform, conc. HCI, R-X, RCOX and nitrous acid (NaNO2/HCI) and test of 10, 20 and 30 amines (nitrous acid test).

(B) Aromatic amine (Aniline)
16.6 Show preparation of aniline from nitrobenzene and phenol.
16.7 State physical properties of aromatic amine.
16.8 Explain chemical properties of aromatic amine, i.e. basicity of aniline, comparison of basic nature of aniline with aliphatic amines and ammonia,alkylation, acylation, diazotization, cartylamines, coupling reaction and electrophilic substitution (Nitration sulphonation and bromination).
16.9 State important uses of aniline.

17. Organometallic Compounds
17.1 Describe briefly the general formula and examples of organolithium, organocopper and organocadmium compounds.
17.2 Explain the nature of Metal-Carbon bond.
17.3 Define Grignard reagent
17.4 Show the preparation Grignard reagent (using haloalkane and haloarene).
17.5 Explain reaction of Grignard reagent with water, aldehydes and ketones (preparation of primary, secondary and tertiary alcohols), carbon dioxide, HCN, RCN, ester and acid chloride

 18. Chemistry in the Service of Mankind
18.1 Explain addition and condensation polymers.
18.2 Explain elastomers and fibres.
18.3 Describe natural and synthetic polymers
18.4 Explain some synthetic polymers (polythene, PVC, Teflon, polystyrene, nylon and bakelite).
18.5 Explain types of dyes on the basis of structure and method of application.
18.6 Describe characteristics of drugs.
18.7 Differentiate natural and synthetic drugs.
18.8 Classify some common drugs.
18.9 Be aware of adverse effect of drug addiction.
18:10 Explain insecticides, herbicides and fungicides

19. Cement
19.1 Explain introduction and raw materials for cement production.
19:2 Give main steps in cement production (crushing and grinding, strong heating and final grinding).
19.3 Explain OPC and PPC cement.
19.4 Explain Portland cement process with flow sheet diagram.
19.5 Explain cement Industry in Nepal.

20. Paper and Pulp
20.1 Explain raw materials, sources of raw materials and stages in production of paper.
 20.2 Give flow-sheet diagram for paper production.
20.3 Describe quality of paper

21. Nuclear Chemistry and Applications of Radioactivity
21.1 Describe natural and artificial radioactivity.
21.2 Give units of radioactivity.
21.3 Explain nuclear reactions.
21.4 Distinguish between nuclear fission and fusion reactions.
21.5 Describe nuclear power and nuclear weapons.
21.6 Explain industrial uses of radioactivity.
21.7 State the medical uses of radioactivity.
21.8 Explain radiocarbon dating
21.9 Describe harmful effects of nuclear radiations.

*Name reactions:
1.Aldol condensation reaction
2.Cannizaro's reaction
3.Perkins condensation
4.Claisen Condensation reaction 
5.Benzoin condensation
6.Carbylamine reaction
7.Reimer Tiemann reaction
8.Coupling reaction( preparation of azo dyes)
9.Diazotization reaction
10. Friedel- Craft's reaction
11. Hoffmann's Bromamide reaction( Decarbonylation reaction)
12. Esterification reaction
13. Carbonylation reaction (Oxo process)
14. Williamsan's etherification reaction
15. Rosenmund reduction

Lab preparation (chemical reaction only) and its chemical properties

1.Chloroform (trichloro methane)
4.Diethyl ether (Ethoxy ethane)
5. Identification of primary, secondary and tertiary alcohols by Victor Meyer's method.
6. Separation of primary, secondary and tertiary amines by Hoffman's method.

Test reaction:
1. Iodoform test 
2.Silver mirror test( reaction with Tollen's reagent) 
3.Nitrous acid test of primary, secondary and tertiary amines.
4. 2,4- DNP test
5.Carbylamine test (test of primary amines)
⚫Reduction of nitrobenzene in different medium.
⚫Preparation of alcohols using Grignard reagent.
⚫Oxidation of alcohols

Reactions to prepare : (with one use)
4. Picric acid
5. Urotropin
6. TNT

⚫1-bromopropane to 2- bromopropane and vice-versa opropanol to 2-propanol and vice versa.
⚫Methanamine 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-hydroxy propanoic acid.
⚫Propanone(acetone) to 2-hydroxy-2-methyl propanoic acid.
⚫Phenol to toulene.
⚫Ethanol to propanol/ propanoic acid.
⚫Methanamide to ethanamine.

Short Questions
1.Why is chloroform stored in a dark bottle containing ethanol?
2. Why does chloroform not give white ppt. with aq. AgNO3?
3. Why is nucleophilic substitution reaction difficult in haloarene? 
4. Why is the boiling point of ethanol greater than that of ethoxy ethane?
5.Why is phenol more acidic than aliphatic alcohol?
6.Why does nitrobenzene undergoes electrophilic substitution reaction at meta position? (Explain why -NO2 group is meta directing towards electrophilic aromatic substitution)
7. Why is chlorobenzene o/p-directing towards erectrophilic substitution reaction?
 8.It is dangerous to boil a sample of ether stored for a long time, give reason.
9.Ether is stored in a bottle containing iron wire, why? 
10.Give a suitable test to distinguish ethylamine from N-methyl methanamine.
11. Write a chemical test to distinguish ethanoic acid(acetic acid) from methanoic
acid(formic acid). 
12. Why is chloroacetic acid stronger than acetic acid?
13. Why is formic acid stronger than acetic acid? 
14. Why amino groups of aniline are protected before nitration?(Aniline can not be nitrated directly, why?) 
15. Write the functional isomers of C3H60 with their IUPAC name. Give a chemical test to distinguish them. 
16. Write an unsymmetrical ether of C3H80. How would you prepare this ether using Williamson's synthesis?
17. Write down possible isomeric amines of C3H9N and give their IUPAC names.
18. What is peptide bond(linkage)? Write an example of dipeptide.
19.What are disaccharides? What happens when a disaccharide is hydrolysed. 20.Define protein. What is meant by denaturation of protein.
21. What is soap? How is soap obtained from fat? (What is saponification?)(What happens when a fat/oil is hydrolysed?)
22.Write monomers and one use of:
⚫ Nylon-6,6
⚫Polyvinyl chloride(PVC) (d) Teflon
23. Write example and one use of:
⚫ Analgesic, antipyretic, antibiotics and antiseptic drugs.
⚫Herbicide and Pesticide
⚫ Germicide and Insecticide
⚫ A synthetic fertilizer - nitrogen fertilizer/Phosphorus (phosphatic) fertilizer, mixed(NPK) fertilizer.


SET A: Extraction of:
⚫(Blister) copper from copper pyrites.
⚫ Steel (Mainly Open Hearth process)
⚫Iron from iron pyrites.
⚫Zinc from zinc blende (sulphide ore). ⚫Mercury from cinnabar (HgS) ore.

SET B: Chemistry of:
⚫Blue vitriol (CuSO4.5H20)
⚫White vitriol (ZnSO4.7H20)
⚫Zinc white (ZnO)
⚫ Calomel (Hg2C12)
⚫Corrosives sublimate (HgCl2)

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 Rinman's green? How is it prepared? Write its one important use.
5. Write a molecular formula of Philosopher's wool. How is it prepared?
 6. What is Nessler's reagent? How is it prepared? Give its one use.
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. Why does silver nitrate produce permanent black stains on the skin?

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