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Phosphorus forms a number of oxoacids. They are hypophosphorous acid (H3PO2), Phosphorous acid (H3PO3), Hypophosphoric acid (H3PO4), pyrophosphoric acid (H4P2O7) and meta phosphoric acid (HPO2)n. 1. Hypo phosphorous acid (H3PO2) or phosphinic acid It is preapred by the oxidation of phosphine by iodine in the presence of calculated amount of water. It is a monobasic acid. PH3 + 2I2 + 2H2O -----------> H3PO2 + 4 HI 2. Phosphorous acid (H3PO3) or phosphonic acid It is prepared by hydrolysis of phosphorous trioxide (P4O6). Phosphorous acid is dibasic. P4O6 + 6H2O ----------> 4H3PO3 3. Hypophosphoric acid (H4P2O6) It is prepared by controlled oxidation of red phosphorous with sodium chlorite solution, when disodium salt of hypophosphoric acid is formed which then passing through cation exchanger yield hypophosphoric acid. Hypophosphoric acid is tetrabasic. 2P + 2NaClO2 + 2H2O ---------> Na2H2P2O6 + 2HCl Na2H2P2O6 + 2H -----resin-----> H4P2O6 + 2Na - resin 4. Orthophosphoric a...

Definition of Micelles (Associated colloids) There are some substances which at low concentrations behave as normal strong electrolytes but at higher concentrations exhibit colloidal behavior due to the formation of aggregated particles. These associated particles are called micelles or associated colloids . The formation of micelles take place only above a particular temperature called Kraft temperature (T K ) and above a particular concentration called critical micelle concentration (CMC). Example: Detergents and soaps. Soap is sodium salt of higher fatty acid like C 17 H 35 COONa (sodium stearate). In aqueous solution soap ionizes as The RCOO - ions (C 17 H 35 COO - ) and Na + ions. C 17 H 35 COONa ---------> C 17 H 35 COO - + Na + The RCOO - ions however consist of two parts. That is, long hydrocarbon chain R(-C 17 H 35 ) also called non-polar tail which is hydrophobic and the polar group COO - called polar-ionic head which is hydrophilic. In concentrated solution,...

Depending upon the nature of interaction between the dispersed phase and the dispersion medium, colloids are classified in to the lyophilic colloids (solvent attracting) and lyophobic colloids (solvent repelling). If water is the dispersion medium, it is called as hydrophilic and hydrophobic colloid respectively. Lyophilic colloids The meaning of the word 'lyophilic' is 'liquid-loving' or 'solvent attracting'. That means, these are colloids in which there is strong interaction between the two phases. Lyophilic colloids are those dispersions in which the dispersed phase exhibits a definite affinity for the medium and as a results extensive solvation of the colloidal particles takes place. They are directly formed by mixing the two phases.Eg :- Gum, soap, starch, gelatin, rubber etc. These sols are also called reversible sols. Because, if the dispersion medium is separated from the dispersed phase, the sol can be reconstituted by simply mixing with the dispersion...

Corrosion Of Iron Corrosion is the process in which a metal is destructed as a result of its reaction with environment. Corrosion of iron is known as rusting. Rusting is the hydrated ferric oxide. Other examples for corrosion are tarnishing of silver and development of green coating on copper and bronze. In corrosion metals undergo anodic oxidation to metal oxides. Electrochemical theory of rusting The rusting of iron is an electrochemical process involving the following steps. The moister containing CO2 acts as electrolyte. H 2 O + CO 2 ------> H 2 CO 3 H 2 CO 3 ------> 2H+ + CO 3 2- The iron is oxidized by the removal of electrons and acts as the anode. Fe ------> Fe 2+ + 2electron The H+ ions from the electrolyte accept electrons from the adjacent areas on metal surface and function as cathode. 4H + + 4electron ------> 2H 2 The atmospheric oxygen moves hydrogen as water. 2H 2 + O 2 ------> 2H 2 O Adding the above two equations, 4H+ +O 2 + 4electron ------> ...

Preparation of phenol from benzene derivatives Phenol was first isolated in the early nineteenth century from coal tar. Nowadays, phenol is commercially produced synthetically. In the laboratory, phenols may be prepared from benzene derivatives by any of the following methods. 1. From sodium benzene sulphonate Benezene sulphonic acid when treated with NaOH gives its sodium salt. Sodium benzene sulphonate. This when fused with NaOH at temperature between 570-620 K, gives sodium phenoxide, which on hydrolysis with dilute mineral acid gives phenol. 2. From Benzene diazonium chloride Benzene diazonium chloride is formed by treating aniline with nitrous acid (NANO2 + HCl) at 273-283 K temperature. On warming an aqueous solution of benzene diazonium chloride, it is hydrolysed to form phenol. 3. From Chlorobenzene (Dow’s process) Chlorobenzene on heating with 10% aqueous solution of NaOH at about 623K under 200 atmospheric pressure in the presence of copper salt catalyst, sodium phenoxide is ...

Preparation of Phenol From Coal Tar Phenol is commercially prepared from the middle oil fraction (443-503K) of coal tar distillate in which it occurs with cresols and naphthalene . First naphthalene is removed by chilling the fraction. The remaining oil is now treated with H 2 SO 4 to remove basic impurities and phenol is then extracted with dilute caustic soda . The aqueous layer is separated and phenol is precipitated with H 2 SO 4 or CO 2 . It is finally purified by distillation. Preparation of Phenol From Cumene Nowadays, phenol is manufactured from the hydrocarbon cumene. Cumene (isopropyl benzene) is first prepared from benzene and propene by Friedel-Crafts reaction in presence of phosphoric acid of aluminum oxide. Cumene is oxidized in presence of air to cumene hydroperoxide, which is then converted to phenol and acetone by treating it with dilute acid. Acetone, a byproduct of this reaction, is also obtained in large quantity by this method. Phenol has a melting point of 3...

Chemical properties of Ethers (With HI) On heating with concentrated Hydrogen iodide (HI) the C-O bond in ethers breaks forming alcohol and alkyl iodide. For example, C 2 H 5 -O-C 2 H 5 + HI ------------> C 2 H 5 - I + C 2 H 5 OH On boiling with excess of concentrated Hydrogen iodide (HI), Alkyl iodide is formed. C 2 H 5 -O-C 2 H 5 + 2HI ------------> 2C 2 H 5 I + H 2 O In the case of mixed ethers with two different alkyl groups, the site of cleavage and hence the alcohol and alkyl iodide that form depend on the nature of the alkyl groups. When one group is methyl and the other is primary or secondary alkyl group, it is the lower alkyl group that forms alkyl iodide due to steric factors. For Example, When one group is methyl and the other alkyl group is a tertiary group, the halide formed is a tertiary group, the halide formed is a tertiary halide. For Example, It is because the attack by I- takes place at that carbon of alkyl group, which has a greater electron pus...