Learn Chemistry with Prof. Kiran Patil

Write the classification of polymers based on intermolecular forces. Give examples. In which classes, are the polymers classified on the basis of intermolecular forces ? Molecular forces bind the polymer chains either by hydrogen bonds or van der Waal's forces. These forces are called intermolecular forces. On the basis of magnitude of intermolecular forces, polymers are further classified as elastomers, fibres, thermoplastic polymers, thermosetting polymers. (1) Elastomers: Weak van der Waals type of intermolecular forces of attraction between the polymer chains are observed in elastomers. When polymer is stretched, the polymer chain stretches and when the strain is relieved the chain returns to its original position. Thus, polymers have elastic character like rubber are called elastomers. Elastomers, the elastic polymers, have weak van der Waal s type of intermolecular forces which permit the poly-mer to be stretched. Elastomers are soft and stretchy and used in making rubber ban...

1 ) Nanoscience: The study of phenomena and manipulation of materials at atomic, molecular and macromolecular scales where properties differ significantly from those at a larger scale is called nanoscience. 2 ) Nanotechnology: The design, characterization, production and application of structures, device and system by controlling shape and size at nanometer scale is called nanotechnology. 3 ) Nanomaterial: A material having structural components with at least one dimension in the nanometer scale that is 1-100 nm is called the nanomaterial. Nanomaterials are larger than single atoms but smaller than bacteria and cells. 4) Nanochemistry: It is the combination of chemistry and nanoscience. It deals with designing and synthesis of materials of nanoscale with different size and shape, structure and composition and their organization into functional architectures.

Trichloro acetic acid is a stronger acid than acetic acid. Explain. (1) The acidic nature of carboxylic acid is due to the ability to release H+ ions. Greater the ease with which they release H+ ions, stronger is the acid. Any factor that stabilizes the carboxylate ion would help the release of H ions and thus increase the strength of the acid. The electron withdrawing group attached to x-carbon atom increases the strength of the acid. In trichloroacetic acid, three chloro substituents on a-carbon atom of acetic acid makes the electrons withdrawing effect more pronounced and the negative charge of carboxylate ion formed gets dispersed. Thus, increases the stability of carboxylate ion. CH3-COOH + H₂O→ CH3-COO- + H₂O 

  Trivial and IUPAC names of ketones Nomenclature of ketones : (A) Common System: (1) Ketones are named according to the alkyl groups attached to the carbonyl carbon atom followed by the word ketone. (2) The substituents in the alkyl groups are indicated by Greek letters α, β, γ, etc. starting from the carbon atom attached to the carbonyl group. (B) IUPAC System: (1) The longest continuous chain containing carbonyl carbon atom is selected as a parent hydrocarbon. (2) 'e' of the alkane is replaced by 'one'. Alkane Alkane. (3) The position of carbonyl group is represented by the lowest location. (4) The substituents in the alkyl groups are prefixed in the alphabetical order along with their positions by appropriate locants. (5) When two C = O groups are present, then ending 'e' of alkane is retained and the suffix -'dione' is added to the name of parent ketone indicating the locants of ketonic carbonyl groups. (6) In case of polyfunctional ketones, higher ...

  Elimination versus substitution : Alkyl halides undergo substitution as well as elimination reaction. Both reactions are brought about by basic reagent, hence there is always a competition between these two reactions. The reaction which actually predominates depends upon following factors. (a) Nature of alkyl halides: Tertiary alkyl halides prefer to undergo elimination reaction whereas primary alkyl halides prefer to undergo substitution reaction. (b) Strength and size of nucleophile: Bulkier electron rich species prefers to act as base by abstracting proton, thus favours elimination. Substitution is favoured in the case of comparatively weaker bases, which prefer to act as nucleophile. (c) Reaction conditions: Less polar solvent, high temperarture favours elimination whereas low temperature, polar solvent favours substitution reaction.

(1) Dichloromethane  (A) Higher levels of dichloromethane in air causes nausea, numbness in fingers and toes, dizziness. (B) Lower levels of dichloromethane causes impaired vision and hearing. (C) Direct contact with eyes can damage cornea. (2) Trichloromethane or chloroform (CHCl 3  (A) When chloroform is exposed to air in the presence of sunlight, it slowly oxidised to phosgene, a poisonous compound, therefore it is stored in dark, amber coloured bottles. (B) Chloroform vapour when inhaled for a short time causes dizziness, headache and fatigue and if inhaled for long time affects central nervous system. (3) Tetrachloromethane or carbon tetrachloride  (A) Exposure to carbon tetrachloride causes eye irritation, damages nerve cells, vomiting sensation, dizziness consciousness or death. Long exposure to chloroform may affect liver. (B) When mixed with air it causes depletion of the ozone layer, which affects human skin leading to cancer. (4) Iodoform  Iodoform has a s...

 

   Methyl alcohol. (1) Methyl alcohol is used as an industrial solvent for dissolving oils, fats, gums, etc. (2) It is used for drycleaning and preparation of perfumes and varnishes. (3) It is used as antifreeze agent for automobile radiators at low temperature. (4) It is used in the preparation of methyl chloride, dimethyl sulphate and formaldehyde. (5) It is used to denature ethyl alcohol. Ethyl Alcohol  (1) Ethyl alcohol is used as solvent for dyes, oils, perfumes, cosmetics and drugs. (2) A mixture of 10-20% ethyl alcohol with petrol is used as motor fuel. (3) A mixture of ethyl alcohol and calcium acetate in gel form is used as solid fuel. (4) It is widely used in beverages (5) Since ethyl alcohol has low freezing point, it is used in thermometer. (6) It is an effective tropical antiseptic therefore it is used in many mouth washes. (7) It kills micro-organisms on wound surface and in the mouth but its low toxicity does not kill the cells of the skin mouth tissues. (8...

Coordination number used in coordination of compounds is somewhat different than that used in solid state.  * In a coordination compound the coordination number is the number of donor atoms of ligands directly attached to metal atom or ion. * In a solid state, the number of closest constituent atoms or ions in contact with a particular atom in the crystal lattice is called coordination number. * In a coordination compound, coordination number depends upon nature of metal atom or ion, and its electronic configuration. * In a solid state, the coordination number depends upon the crystalline structure of the unit cell.

 Chapter wise distribution of marks in chemistry question paper  1) Solid State     Marks 3     Option 5 2) Solutions  Mark 4 Option 6 3) Ionic Equilibria Marks 4 Options 6 4)chemical Thermodynamics Mark 6 Option 8 5 ) Electrochemistry Marks 5 Options 8 6) Chemical Kinetics Marks 6 Option 7 7 ) Elements of Groups 16, 17 and 18 Marks 6 Options 8 8 )Transition and Inner Transition Elements Marks 6 Options 8 9 ) Coordination Compounds Marks 5 Option 7 10 )Halogen Derivatives Marks 5 Options 7 11):Alcohols, Phenols and Ethers Marks 4 Options 6 12 ) Aldehydes, Ketones and Carboxylic Acids Marks 6 Options 8 13 )Amines Marks 3 Options 4 14 )Biomolecules Marks 3 Options 4 15 ) Introduction to Polymer Chemistry. Marks 3 Options 4 16 ) Green Chemistry and Nanochemistry Marks 3 Options 4 Total marks 70 Marks with Options 98

EVALUATION PLAN  1. (a) Theory/Written examination (3 hours) 70 marks (b) Practical examination (3 hours): 30 marks Total : 100 marks Question paper pattern for the theory / written examination : Section A Multiple Choice Questions (MCQs) Q. 1.  [(i) to (x)] 10 Marks  Very Short Answer Questions.. Q. 2. [(i) to (viii)] 8 Marks Section B Short Answer Questions ( Any Eight ) Q. 3. to Q. 14. Section C Short Answer Questions ( Any Eight ) Q. 15. to Q. 26. Section D Long Answer Questions ( Any Three ) Q. 27. to Q. 31. Total Marks --70.. Marks with option-- 98.!