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S.DAS WEB is a trusted place for Science discussion. Everyone can visit, download and share a lot of science related informations from our Website. Here you can get Physics, Chemistry, Biology and every science related knowledge. You find every chapter wise descriptions of Biology. Biology syllabus- 1. The living world 2. Biological classification 3. Plant Kingdom 4. Animal Kingdom 5. Structural organization in Plants and animals. 6. Morphology of Flowering Plants 7. Anatomy of Flowering Plants 8. Cell, the unit of life 9. Biomolecules 10. Cell cycle and cell division 11. Physiology of plant and Human 12. Transport in plant 13. Mineral Nutrition 14. Photosynthesis 15. Photorespiration 16. plant growth and development 17. Digestion and Absorption 18. Breathing and Exchange of gases 19. Body fluids and circulation 20. Excretion and Elimination 21. Locomotion and movement 22. Nervous System 23. Hormone 24. Reproduction in organisms 25. Sextual Reproduction in Plants 26. Human Reproduction 27. Reproductive health and process 28. Inheritance and Variation 29. Molecular basis of inheritance 30. Evolution and mechanism 31. Human Disease 32. Ford production and Agricultural use 33. Microbes in Human welfare 34. Biotechnology 35. Population and its controls 35. Ecosystem 36. Biodiversity and Conservation 37. Environmental Science. Chemistry Syllabus- 1. Structure of atom 2. Periodic table 3. Chemical Bonding and molecular structure 4. States of gases and liquids 5. Thermodynamics 6. Equilibrium 7. Reduction and Oxidation reactions 8. Hydrogen 9. s-block alkali and alkaline metals 10. p-block elements 11. Organic Chemistry 12. Hydrocarbons.KingRoot is an application that lets you root your Android device in a matter of seconds, as long as you have an operating system between Android 4.2.2and Android 5.1. This means that this app lets you do the same thing as the classicTowelroot, but you can use it even if you have Lollipop.The procedure to root your device is as simple as Towelroot. Even if the app is entirely in Chinese, the only thing you have to do is press on the blue button and wait. After a couple of seconds, the application finishes working and you'll have your rooted device.It's importantto know that KingRoot doesn't work with all type devices. On Moto G, for instance, it usually has some trouble. With Nexus, though, it usually works perfectly.KingRoot is an excellent way to root your Android device. That said, rooting a device is always a delicate process, so do it with care and be conscious of the risks involved.Codariocalyx motorius, known as the telegraph plant or semaphore plant, is a tropical Asian shrub, one of a few plants capable of rapid movement; others include Mimosa pudica and the venus flytrap Scientific name: Codariocalyx motorius Click below for more subjects Grade Lists KL magazine Home Grade 12 Chemistry Haloalkanes and Haloarenes Preparation of DDT, BHC and IodoformNote on Preparation of DDT, BHC and IodoformFound mistakes?? Report Here Note Things to rememberDichloro-Diphenyl trichloroethane (DDT).Its structure istyIUPAC name of DDT is 2,2-bis(p-Chlorophenyl)-1,1,1-trichloroethane)DDT.Preparation.It is prepared by heating a mixture of choral and chlorobenzene in the molar ratio (1:2) in the presence of concentration H2SO4.hgProperties and uses of DDT.It is an odourless white crystalline solid with melting point 1090C. It is almost insoluble in water but readily dissolves in benzene, kerosene oil, alcohol, etc. DDT is a powerful contact insecticide and is widely used for killing mosquito and other insects.DDT is not biodegradable. Its residue accumulates in the environment and its long-term effect could be highly dangerous. It has been provided to be toxic to living beings. In human beings, it disturbs the sex hormones. DDT is still being widely used in poor countries due to non-availability of other cheaper insecticides.BHC.It is prepared by chlorination of benzene in presence of sunlight.yhgIUPAC name of BHC is 1,2,3,4,5,6 Hexachlorocyclohexane(Benzene hexachloride)Benzene hexachloride is a cyclohexane derivative and nine stereoisomers are possible. However, only five of them have been actually isolated from the mixture. They are called α, β, γ, Δ, ε forms. The mixture of stereoisomeric hexachlorides is an active component in BHC is γ isomer, called gammaxene or lindane.Uses.BHC is an important agricultural pesticide mainly used for exterminating white ants, leaf hopper, termite etc.preparation..In the laboratory, iodoform is prepared by the action of iodine on ethyl alcohol or acetone in the presence of an alkali. The reaction is known as iodoform reaction.1. From ethyl alcohol.Reactions involved in the preperation of iodoform from ethyl alcohol are.2NaOH+I2→NaOI+NaI+H2OWhereNaOI=SodiumhypoioditeCH3CH2OH+NaOI−→−−−−−OxidationCH3CHO+NaI+H2OWhereCH3CH2OH=ethanolCH3CHO=EthanalCH3CHO+3NaOI−→−−−−−IodinationCl3CHO+3NaOHWhereCl3CHO=TriiodoethanalCl3CHO+NaOHxrightarrowHydrolysisCHI3+HCOONaWhereCHI3=IodoformWhereHCOONa=SodiumformateThe overall reaction may be written as.CH3CH2OH+4I2+6NaOH−→−heatCHI3+5NaI+5H2O+HCOONaWhereCH3CH2OH=ethylethanolCHI3=IodoformHCOONa=Sodiumformate2. From acetone.Reaction involved in the preparation of iodoform from acetone are2NaOH+I2→NaOI+NaI+H2OCH3COCH3+3NaOI−→−−−−−IodinationCl3COCH3+3NaOHWhereCl3COCH3=TriiodoacetoneCl3COCH3+NaOH−→−−−−−HydrolysisCHI3+CH3CooNaWhereCHI3=IodoformCH3COONa=SodiumacetateThe overall reaction may be represented as.CH3COCH3+3I2+4NaOH−→−heatCHI3+3NaI+CH3COONaWhereCH3COCH3=AcetoneCHI3=IodoformCH3COONa=SodiumacetateIn th above reaction sodium carbonate can also be used in place of NaOH or KOH). If sodium carbonate is used the overall reactions are.CH3CH2OH+4I2+3Na2CO3−→−heatCHI3+HCOONA+5NaI+2H2O+3CO2WhereCH3CH2OH=ethanol(Ethylalcohol)CH3COCH3+3I2+2Na2CO3−→−heatCHI3+CH3COONa+3NaI+2Co2WhereCH3COCH3=Propanone(Acetone)Properties of Iodoform.Physical property.The importance of physical property of iodoform is listed below. Iodoform is a pale yellow coloured crystalline solid with characteristic unpleasant odour. It is insoluble in water but soluble in ethanol and ether. Its melting point is 1190C. It has an antiseptic action due to the liberation of free iodine.Chemical property.Some important chemical property of Iodoform is as follows.1. Stability.It is not a very stable compound. On heating decomposes to give iodine vapours. The decomposition accelerates in presence of moisture, light, and air.4CHI3+5O2−→−−Heat6I2+4CO2+2H2O2. Hydrolysis.Iodoform on boiling with alcoholic or concentrated aqueous solution of KOH give potassium formate.CHI3+3KOH−→−BoilHCOOH+3KI+H2OHCOOH+KOH→HCOOK+H2O3. Reduction.Iodoform on reduction with red phosphorus and hydriodic acid gives diiodomethane.CHI3+2[H]−→−−−−RedPHICH2I2+HI4. Action with silver power.Iodoform oh cheating with silver power forms acetylene.2CHI3+6Ag−→−heatCH≡CH+6AgIWhereCH≡CH=Ethyne(Acetylene)Uses of Iodoform.Som,e of the important uses of Iodoform are as follows. It is used as in antiseptic for dressing wounds and this nature is due to iodine that it liberates. However, of its unpleasant smell, it has now been replaced by better antiseptic. It is used in the manufacture of pharmaceuticals.Reference.Bahl, B S, Bahl, and Arun. Advanced Organic chemistry. S. Chand and company Ltd., n.d.Sthapit, M K, R R Pradhananga, and K B Bajracharya. Foundations of chemistry. Taleju Prakashan, n.d.Tewari, K S, S N Mehrotra, and N K Vishnoi. A textbook of organic chemistry. Vikash publishing House Pvt. ltd., n.d.Verma, N K and S K Khanna. Compressive chemistry. 8th edition. Laxmi publications P. Ltd., 1999.DISCUSSIONS ABOUT THIS NOTENo discussion on this note yet. Be first to comment on this noteRelated NotesDefination and types of haloalkanes.Grade 12 » Chemistry» Haloalkanes and HaloarenesGo to Note »Nomenclature and isomerism of haloalkaneGrade 12 » Chemistry» Haloalkanes and HaloarenesGo to Note »Preparation of Haloalkanes.Grade 12 » Chemistry» Haloalkanes and HaloarenesGo to Note »What is Telegraph plant? Where can it be found? Why is it called 'Telegraph' and 'Dancing tree'?PhotoperiodismIt has been discovered that duration of light also plays a major role in inducing flowering in plants. This flowering response in plants to the relative length of light and dark periods within a 24 hour cycle is called ‘Photoperiodism’. Every plant has a specific critical period of light duration needed for flowering. In order to flower they must be exposed to either more or less light hour than that of critical period. Based on flowering response to light duration, plants have been classified into Long day plants, short day plants and day neutral plants.Long day plants (LDP)They are plants which produce flower only when they are exposed to light duration more than the critical period. They produce flower in summer. E.g.-Oat and Rye plants.Short day plants (SDP)They are plants which produce flower only when they are exposed to light duration shorter than the critical period. They produce flower in spring or winter. E.g.- Chrysanthemum, Tobacco and Coffee.Day neutral plantsThey produce flowers throughout the year irrespective of length of light hours to which they are exposed. E.g.- TomatoVernalisationSome biennials like carrot, cabbage and sugar beet need a cold/low temperature treatment before they flower. This is called ‘Vernalisaion’. In other words, Vernalisation is promotion of flowering by low temperature treatment. Spraying gibberellins is a substitute to cold treatment and biennials can be made to flower in one year without the cold treatment.