Wednesday, 1 September 2021

GREAT TIPS FOR STUDENTS OF CLASS XII FOR STUDYING CHEMISTRY

      








1. Know the marks of each chapter: Following four units collectively have 19 marks (~ 27%) 

Unit VI   General Principles and Processes of Isolation of Elements
Unit VII   p-Block Elements
Unit VIII d -and f -Block Elements          
Unit IX Coordination Compounds 

The key points to be learnt in these units are listed below-

General Principles and Processes of Isolation of Elements- froth flotation process, leaching, roasting, calcination, smelting, vapor phase refining, zone refining, extraction of aluminium, extraction of copper
Some p -Block Elements 
Group -15 Elements: Anomalous properties of Nitrogen,  Comparision of properties of Hydrohen compounds of  group 15 elements (M)Nitrogen preparation properties and uses; compounds
of Nitrogen, preparation and properties of Ammonia and Nitric Acid, Oxides of Nitrogen(Structure
only) ; Phosphorus - allotropic forms, compounds of Phosphorus: Preparation and Properties of
Phosphine, Halides and Oxoacids (elementary idea only). 

Group 16 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. 






Ø      In organic chemistry, stress must be laid on the following name reactions. Brown Hydroboration, Carbylamine Reaction (Isocyanide Test), Cannizzaro Reaction, Clemmensen Reduction, Coupling Reaction, Rosenmund’s Reaction, Riemer-Tiemann Reaction, Friedel-Crafts Acylation Reaction, Gabriel Phthalimide Reaction, Hinsberg’s Test, Hoffmann Bromamide Reaction, Sandmeyer’s Reaction, Diazotization. These not only help in organic conversions but also in solving word problems. Distinction between pair of compounds and mechanism of organic reactions for one or two marks is generally asked in the examination 
Ø      Revisit Class XI concepts like hyperconlugation, inductive effect & resonance or mesomeric effect with reference to organic compounds to master reasoning questions. This helps in understanding the basic character of amines, acidity of carboxylic acids relative stability of molecules and reactivity of molecules 
Ø      From the physical chemistry portion, basic laws such as Raoult’s law, Henry’s law, Kohlrausch’s law, degree of dissociation, problems based on Nernst equation, colligative properties involving association and dissociation (Vant Hoff factor) should be thoroughly practised. Not more than 12 marks numerical problems are expected in the board paper 
Ø      Approximately 10 marks are reserved for higher order thinking skill questions 
Ø      Value-based questions are expected from any chapter of the prescribed syllabus 
Ø      Last three chapters can be really scoring as these constitute slightly more than 14% of the total paper 
Ø      If you have followed a study routine and have been revising your class work, there should be no need to worry. Try to keep yourself calm, positive and confident 

FOR EXAMINATION
Ø  Be systematic. Do not overwrite or cut Follow a sequence — write answers in ascending or descending order. Do not shuffle Do not mix questions of one part with another. This is strictly prohibited by CBSE 
Ø      Show proper working notes. Calculations carry marks if they have been asked for specifically in the question 
Ø      Write the formulae even if you are not sure of final answer. Formulae carry marks like in ratio analysis 
Ø      Do not leave any question, even if there is error in question