Solved question paper for Chemistry Mar-2021 (PSEB Class 12th)
Solved Question Paper
Chemistry Mar-2021
PSEB • Class 12th • 1st • Mar-2021
Chemistry previous year question papers on BRpaper help students looking for PSEB 12th Class Question Papers to browse Chemistry papers for board exam practice and revision. This subject section is useful for finding PSEB 12th Chemistry old question papers, PYQ-style papers, and related exam-preparation material where available, so students can study the question format, recurring topics, and marks pattern used in the Punjab board exam. If you are preparing for the Punjab School Education Board Class 12 Chemistry paper, this page can help you compare past question styles with sample paper and model paper trends, and focus on important questions more confidently. BRpaper is not the official website of Punjab School Education Board or any institution, and it does not publish official notices or academic updates.
Unit-I: Solid, State
Classification of solids based on different binding forces: molecular, ionic, covalent and metallic solids, amorphous and crystalline solids (elementary idea), unit cell in two dimensional and three dimensional lattices, calculation of density of unit cell, packing in solids packing efficiency, voids, number of atoms per unit cell in a cubic unit cell, points defects, electrical and magnetic properties. Band theory of metals, conductors, semiconductors and insulators and n and p type semiconductors.
Unit II: Solutions
Types of solutions, expression of concentration of solutions of solids in liquids, solubility of gases in liquids, solid solutions, colligative
properties - relative lowering of vapour pressure, Raoults Law, elevation of B.P., depression of freezing point, osmotic pressure, determination of molecular masses using colligative properties, abnormal molecular mass. Vant Hoff factor.
Unit III: Electrochemistry
Redox reactions; conductance in electrolytic solutions, specific and molar conductivity, variations of conductivity with concentration, Kohlrausch's Law, electrolysis and laws of electrolysis (elementary idea) dry cell-electrolytic cells and Galvanic cells; lead accumulator, EMF of a cell, standard electrode potential, Nernst equation and its application to chemical cells, fuel cells; corrosion. Relation between Gibbs Energy change and EMF of cell.
Unit IV: Chemical Kinetics
Rate of a reaction (average and instantaneous), factors affecting rates of reaction; concentration, temperature, catalyst; order and molecularity of a reaction: rate law and specific rate constant, integrated rate equations and' half life (only for zero and first order reactions); concept of collision theory (elementary idea, no mathematical treatment). Activation Energy, Arrhenious equation.
Unit V: Surface Chemistry
Absorption physiorption and chemisorption; factors affecting adsorption of gases on solids; catalysis; homogenous and heterogeneous,
activity and selectivity; enzyme catalysis; colloidal state: distinction between true solutions, colloids and suspensions; lyophillic, lyophobic, multimolecular and macromolecular/colloids; properties of colloids; Tyndall effect, Brownian movement, electrophoresis, coagulation; emulsion-types of emulsions.
Unit VI: General Principles and Processes of Isolation of Elements
Principles and methods of extraction – concentration, oxidation, reduction electrolytic method and refining; occurrence and principles of
extraction of aluminum, copper, zinc and Iron.
Unit VII: p-Block Element
Group 15 elements: General introduction, electronic configuration, occurrence, oxidation states, trends in physical and chemical
properties; nitrogen - preparation, properties and uses; compounds of nitrogen- preparation and properties of ammonia and nitric acids, oxides of nitrogen (structure only); Phosphorous-allotropic forms; compounds of phosphorous preparation and properties of phosphine, halides (PCl3,PCl5) and oxoacids (elementary idea only).
Group16 elements: General introduction, electronic configuration, oxidation states, occurrence, trends in physical and chemical
properties; dioxygen; preparation, properties and uses; classification of oxides; Ozone. Sulphur - allotropic forms; compounds of sulphur preparation, properties and uses of sulphur dioxide, sulphuric acid, industrial process of manufacture, properties and uses, oxoacids of sulphur (structures only).
Group 17 elements: (General introduction, electronic configuration, oxidation states, occurrence, trends in physical and chemical
properties; compounds of halogens; preparation, properties and uses of chlorine and hydrochloric acid, interhalogen compounds, oxoacids of halogens (structures only).
Group 18 elements: General introduction, electronic configuration. Occurrence, trends in physical and chemical properties, uses.
Unit-VIII: d and f Block Elements
General introduction, electronic configuration, occurrence and characteristics of transition metals, general trends in properties of the first
row transition metals-metallic character, ionization, enthalpy, oxidation states, ionic radii, colour, catalytic properties, magnetic properties, interstitial compounds, alloy formation. Preparation and properties of K2Cr2O7,and KMnO4. Lanthanoids - electronic configuration, oxidation states, chemical reactivity and lanthanoid contraction and consequences. Actenoids - Electronic configuration, oxidation states.
Unit-IX: Coordination Compounds
Coordination compounds - introduction, ligands, coordination number, colour, magnetic properties and shapes, IUPAC nomenclature of mononuclear coordination compounds, bonding; Werner’s theory VBT, CFT, Isomerism (structure and stereo) importance of coordination compounds (in qualitative analysis, extraction of metals and biological systems).
Unit-X: Haloalkanes and Haloarenes.
Haloalkanes: Nomenclature, nature of C-X bond, physical and chemical properties, mechanism of substitution reactions, optical rotation. Halearenes: Nature of C-X bond, substitution reactions (directive influence of halogen for monosubstituted compounds only) Uses and environmental effects of - dichloromethane, trichlromethane, tetrachloromethane, iodoform, freons, DDT.
Unit –XI: Alcohols, Phenols, and Ethers
Alcohols: Nomenclature, methods of preparation, physical and chemical properties (of primary alcohols only); identification of primary, secondary and tertiary alcohols; mechanism of dehydration, uses, with special reference to - methanol and ethanol. Phenols: Nomenclature, methods of preparation, physical and chemical properties, acidic nature of phenol, electrophilic substitution reactions, uses of phenols. Ethers: Nomenclature, methods of preparation, physical and chemical properties, uses.
Unit-XII: Aldehydes, Ketones aml Carboxylic Acids
Aldehydes and Ketones: Nomenclature, nature of carbonyl group, methods of preparation, physical and chemical properties, and mechanism of nucleophilic addition, reactivity of alpha hydrogen in aldehydes; uses. Carboxylic Acids: Nomenclature, acidic nature, methods of preparation, physical and chemical properties; uses.
Unit-XIII: Organic compounds containing Nitrogen
Amines: Nomenclature, classification, structure, methods of preparation, physical and chemical properties, uses, identification of primary,secondary and tertiary amines. Cyanides and Isocyanides - will be mentioned at relevant places in context. Dizonium Salts: Preparation, chemical reactions and importance in synthetic organic chemistry.
Unit-XIV: Biomolecules
Carbohydrates - Classification (aldoses and ketoses), monosaccaharides (glucose and fructose), oligosaccharides (sucrose, lactose, maltose), polysaccharides (starch, cellulose, glycogen); importance Proteins - Elementary idea of amino acids, peptide bond,polypeptides proteins, primary structure, secondary structure, tertiary structure and quaternary structure (qualitative idea only), denaturation of proteins; enzymes. Vitamins: Classification and functions. Harmones: Elementary idea (excluding structure) Nucleic Acids: DNA & RNA .
Unit-XV: Polymers
Classification - natural and synthetic, methods of polymerization (addition and condensation), copolymerization. Some important polymers; natural and synthetic like polythene, nylon, polyesters, bakelite, rubber. Biodegradable and Non- Biodegradable Polymers. Unit-XVI: Chemistry in everyday life :
1. Chemicals in medicines analgesic, transquilizers, antiseptics, disinfectants, antimicrobials, antifertility drugs, antibiotics, antacids,
antihistamines.
2. Chemicals in food- preservatives, artificial sweetening agents. Elementary idea of antioxidents.
3. Cleansing agents- soaps and detergents, cleansing action.
Solved Questions
Solved-
Which type of colloids are stable in nature?Short Answer Mar-2021 • PSEB Class 12th
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Mar 2021 Which type of colloids undergo solvation?
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Define lyophilic colloids.Short Answer 1 Marks Mar-2021 • PSEB Class 12th
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Which type of colloids undergo solvation?Short Answer 1 Marks Mar-2021 • PSEB Class 12th
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Mar 2021 Which type of colloids are stable in nature?
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What are protective colloids?Short Answer Mar-2021 • PSEB Class 12th
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Mar 2021 How protection of colloids can be done?
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How protection of colloids can be done?Short Answer 1 Marks Mar-2021 • PSEB Class 12th
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Mar 2021 What are protective colloids?
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The C-X bond length in halobenzene is smaller than C-X bond length in CH3-XTrue / False 1 Marks Mar-2021 • PSEB Class 12th
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Alcohols are weaker acids than waterTrue / False 1 Marks Mar-2021 • PSEB Class 12th
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Carboxylic acids are more acidic than phenols.True / False 1 Marks Mar-2021 • PSEB Class 12th
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Keratin is fibrous proteinTrue / False 1 Marks Mar-2021 • PSEB Class 12th
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Aliphatic Amines are more basic than NH3True / False 1 Marks Mar-2021 • PSEB Class 12th
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which of the following aqueous solutions have should have the highest boiling point : (a) 1.0 M NaOH (b) 1.0 M Na2SO4 (c) 1.0 M NH4NO3 (d) 1.0 M KNO3MCQ 1 Marks Mar-2021 • PSEB Class 12th
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Mar 2021 which of the following aqueous solutions have should have the highest \r\nboiling point : \r\n(a) 1.0 M NaOH \r\n(b) 1.0 M Na2SO4 \r\n(c) 1.0 M NH4NO3 \r\n(d) 1.0 M KNO3
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The value of Henry’s constant : (a) Increases with increase in temp (b) decreases with increase in temp (c) remains contant (d) first increases the decreasesMCQ 1 Marks Mar-2021 • PSEB Class 12th
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Mar 2021 The value of Henry’s constant :\r\n(a) Increases with increase in temp \r\n(b) decreases with increase in temp \r\n(c)remains contant \r\n(d) first increases the decreases
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18 g of glucose is dissolved in 1kg of water at what temp will the water boil , kb for water is 0.52 K kg mol-1 (a) 373.2 K (b) 378.2 K (c) 381.5 K (d)MCQ 1 Marks Mar-2021 • PSEB Class 12th
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Mar 2021 18 g of glucose is dissolved in 1kg of water at what temp will the water boil , \r\nkb for water is 0.52 K kg mol-1\r\n(a)373.2 K \r\n(b) 378.2 K \r\n(c) 381.5 K
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Which of the followings oxidation state of oxygen is +2 (a) Cl2O (b) O2F2 (c) OF2 (d) N2OMCQ 1 Marks Mar-2021 • PSEB Class 12th
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Mar 2021 Which of the followings oxidation state of oxygen is +2\r\n(a) Cl2O \r\n(b) O2F2 \r\n(c) OF2 \r\n(d) N2O
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Ethanol upon heating with conc. H2SO4 at 443 k gives: (a) Diethyl ether (b) Ethylene (c) Ethyl hydrogen sulphate (d) none of theseMCQ 1 Marks Mar-2021 • PSEB Class 12th
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Mar 2021 Ethanol upon heating with conc. H2SO4 at 443 k gives:\r\n(a) Diethyl ether \r\n(b) Ethylene\r\n(c) Ethyl hydrogen sulphate \r\n(d) none of these
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Oxidation state of Fe in [Fe(CN)6 ]3-MCQ 1 Marks Mar-2021 • PSEB Class 12th
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Lyophilic sols are more stable than lyophobic sols. This is due to the fact that lyophilic colloids are extensively solvated, i.e., colloidal particles are covered by a sheath of the liquid in which they are dispersed.Lyophilic colloids have a unique property of protecting lyophobic colloids. When a lyophilic sol is added to the lyophobic sol, the lyophilic particles form a layer around
lyophobic particles and thus protect the latter from electrolytes. Lyophilic colloids used for this purpose are called protective colloids.
Answer the followings
Which type of colloids are stable in nature?
Define lyophilic colloids.
Which type of colloids undergo solvation?
What are protective colloids?
How protection of colloids can be done?Very Short Answer 5 Marks Mar-2021 • PSEB Class 12th -
True/False
The C-X bond length in halobenzene is smaller than C-X bond length in CH3-X (T/F)
Alcohols are weaker acids than water (T/F)
Carboxylic acids are more acidic than phenols. (T/F)
Keratin is fibrous protein ( T/F)
Aliphatic Amines are more basic than NH3 ( T/F)True / False 5 Marks Mar-2021 • PSEB Class 12th -
which of the following aqueous solutions have should have the highest
boiling point :
(a) 1.0 M NaOH
(b) 1.0 M Na2SO4
(c) 1.0 M NH4NO3
(d) 1.0 M KNO3Very Short Answer 1 Marks Mar-2021 • PSEB Class 12th-
Mar 2021 which of the following aqueous solutions have should have the highest boiling point : (a) 1.0 M NaOH (b) 1.0 M Na2SO4 (c) 1.0 M NH4NO3 (d) 1.0 M KNO3
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Colligative properties depends upon :
(a) Nature of solute particles present in the solution
(b) Nature of solute particles present in the solution
(c) Physical properties of the solute particles
(d) Nature of the solvent particlesVery Short Answer 1 Marks Mar-2021 • PSEB Class 12th -
The value of Henry’s constant :
(a) Increases with increase in temp
(b) decreases with increase in temp
(c)remains contant
(d) first increases the decreasesVery Short Answer 1 Marks Mar-2021 • PSEB Class 12th-
Mar 2021 The value of Henry’s constant : (a) Increases with increase in temp (b) decreases with increase in temp (c) remains contant (d) first increases the decreases
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18 g of glucose is dissolved in 1kg of water at what temp will the water boil ,
kb for water is 0.52 K kg mol-1
(a)373.2 K
(b) 378.2 K
(c) 381.5 KVery Short Answer 1 Marks Mar-2021 • PSEB Class 12th-
Mar 2021 18 g of glucose is dissolved in 1kg of water at what temp will the water boil , kb for water is 0.52 K kg mol-1 (a) 373.2 K (b) 378.2 K (c) 381.5 K (d)
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Which of the followings oxidation state of oxygen is +2
(a) Cl2O
(b) O2F2
(c) OF2
(d) N2OVery Short Answer 1 Marks Mar-2021 • PSEB Class 12th-
Mar 2021 Which of the followings oxidation state of oxygen is +2 (a) Cl2O (b) O2F2 (c) OF2 (d) N2O
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Ethanol upon heating with conc. H2SO4 at 443 k gives:
(a) Diethyl ether
(b) Ethylene
(c) Ethyl hydrogen sulphate
(d) none of theseVery Short Answer 1 Marks Mar-2021 • PSEB Class 12th-
Mar 2021 Ethanol upon heating with conc. H2SO4 at 443 k gives: (a) Diethyl ether (b) Ethylene (c) Ethyl hydrogen sulphate (d) none of these
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Oxidation state of Fe in [Fe(CN)6 ]3-
(a) +3
(b) +2
(c) +4
(d) -3Very Short Answer 1 Marks Mar-2021 • PSEB Class 12th -
IUPAC name of the complex K3[Fe(CN)6 ] is
(a) potassium hexacyanoferrate (II)
(b) potassium hexacyanoferrate (III)
(c)potassium hexacyanoiron (II)
(d) tripotassium hexacyanoiron (II)Very Short Answer 1 Marks Mar-2021 • PSEB Class 12th -
Which among the followings is disaccharides
(a) Glucose
(b) cellulose
(c) Sucrose
(d) starchVery Short Answer 1 Marks Mar-2021 • PSEB Class 12th -
Which among the followings is globular protein ?
(a) Albumin
(b) Keratin
(c) collagen
(d) None of the aboveVery Short Answer 1 Marks Mar-2021 • PSEB Class 12th -
Which among the following is secondary amine:
(a) CH3NH2
(b) ( CH3)3N
(c) CH3NHCH3
(d) CH3CH2NH2Very Short Answer 1 Marks Mar-2021 • PSEB Class 12th -
Alkyl cyanide upon reduction with Na/ethanol gives
(a) Carboxylic acids
(b) primary amines
(c) sec- amine
(d) tert-amineVery Short Answer 1 Marks Mar-2021 • PSEB Class 12th -
Which among the followings is most acidic?
(a) Acetic acid
(b) Formic acid
(c) Chloroacetic acid
(d) EthanolVery Short Answer 1 Marks Mar-2021 • PSEB Class 12th -
Which among the followings undergoes cannizzaro’s reaction?
(a) Ethanal
(b) Benzaldehyde
(c) Propanal
(d) None of aboveVery Short Answer 1 Marks Mar-2021 • PSEB Class 12th -
When alipahtic aldehydes are treate with fehling solution, following observation is obtained
(a) White ppt
(b) red coluration
(c) Orange colouration
(d) Brown colurationVery Short Answer 1 Marks Mar-2021 • PSEB Class 12th -
In Clemmensen reduction the reducing agent used is
(a) Na / ethanol
(b) Zn-Hg /HCl
(c) Mg-Hg/H2O
(d) LiAlH4Very Short Answer 1 Marks Mar-2021 • PSEB Class 12th -
One Faraday contains the charge
(a) 95000C
(b) 96500 C
(c) 94500 C
(d) 95600 CVery Short Answer 1 Marks Mar-2021 • PSEB Class 12th -
XeF2 has linear structure because
(a) Xe is sp3d2 hybridized having 6 bp and 1lp
(b) Xe is sp3d2 hybridized having 4 bp and 2 lp
(c) Xe is sp3d hybridized having 2 bp and 3 lp
(d) Xe is sp3 hybridized having 3 bp and 1lpVery Short Answer 1 Marks Mar-2021 • PSEB Class 12th -
The vapour pressure of 2.1% of an queous solution pf a non electrolyte at 373 k is 755 mm calculate the molar mass of solute
OR
When 1.80 gm of non volatile compound is dissolved in 25 g of acetone, the solution boils at 56.86 C while pure acetone boils at 56.38 C under the same atmospheric pressure calculate the molar mass of the compound .Kb for acetone is 1.72 K kg mol-1Short Answer 2 Marks Mar-2021 • PSEB Class 12th -
What is specific conductance of a solution ? How it varies with dilution ?Short Answer 2 Marks Mar-2021 • PSEB Class 12th
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A first order reaction is found to have a rate constant k =5.5 X10-14 sec-1
Find the half life period
OR
A first order reaction is 75% completed in 40 minutes , calculate its half life
periodShort Answer 2 Marks Mar-2021 • PSEB Class 12th -
Why does NCl5 not exist ?
OR
Oxygen is a gas while sulphur is solid . explainShort Answer 2 Marks Mar-2021 • PSEB Class 12th -
Why nitrous acid is oxidant as well as reductant ?
OR
What is the basicity of H3PO4 and why ?Short Answer 2 Marks Mar-2021 • PSEB Class 12th -
Why transition metals act as good catalysts?Short Answer 2 Marks Mar-2021 • PSEB Class 12th
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Why are Mn2+ compounds more stable than Fe2+ towards oxidation to their +3 state?Short Answer 2 Marks Mar-2021 • PSEB Class 12th
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What is meant by unidentate and ambidentate ligands? Give two examples for each.
OR
[Fe(CN)6]4–and [Fe(H2O)6]2+ are of different colours in dilute solutions. Why?Short Answer 2 Marks Mar-2021 • PSEB Class 12th -
Explain the factors affecting rate of a reaction.Short Answer 2 Marks Mar-2021 • PSEB Class 12th
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Calculate the potential of hydrogen electrode in contact with a solution whoseLong Answer 3 Marks Mar-2021 • PSEB Class 12th
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Compare and explain the reactivity OR different alcohols towards sodium.Long Answer 3 Marks Mar-2021 • PSEB Class 12th
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For a first order reaction, show that time required for 99% completion is twice the time required for the completion of 90% of reaction.
OR
A first order reaction takes 40 min for 30% decomposition.
Calculate half life period.Long Answer 3 Marks Mar-2021 • PSEB Class 12th -
Why is dioxygen a gas but sulphur a solid?Long Answer 3 Marks Mar-2021 • PSEB Class 12th
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Explain giving reasons-
(i) Transition metals and many of their compounds show paramagnetic behav iour. (1)
(ii) The enthalpies of atomisation of the transition metals are high. (2)
(iii) The transition metals generally form coloured compounds. (2)
OR
(i) n-butyl chloride is treated with alcoholic KOH
(ii) bromobenzene is treated with Mg in the presence of dry ether
(iii) ethyl chloride is treated with aqueous KOHis act as good catalyst.(2)
(iv) methyl bromide is treated with sodium in the presence of dry ether strongly oxidis
(v) methyl chloride is treated with KCN ?
(vi) The d' configuration is very unstable in ions.(1)Long Answer 5 Marks Mar-2021 • PSEB Class 12th
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