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Production of Sulphuric Acid (H 2 SO 4 ) Sulphuric acid is an important chemical used in industry. It is also known as 'King of chemicals'. Sulfuric acid is manufactured by contact process . Contact process Involves the following steps. Preparation of Sulphurdioxide (SO 2 ) SO 2 is prepared by burning sulphur or sulphide ore in excess of air. It is done in a sulphur burner. S + O 2   ----------->  So 2 So 2 produced is purified by passing it through 1. Dust precipitator (which removes dust from gas) 2. Water scrubber (which removes soluble impurities) 3. Drying tower (which removes moisture) 4. Arsenic purifier (which removes arsenic impurities) Oxidation of SO 2 to SO 3 Purified SO 2 gas coming out from arsenic purifier is preheated and admitted to catalytic converter filled with catalyst V 2 O 5 . In catalytic chamber the following reversible reaction take place and is known as Contact process . 2SO 2 + O 2   <========>...

Sulphur hexaflouride (SF6) and Sulfur tetrafluoride (SF4) Sulphur forms a number of halides in which the oxidation state of sulphur are +1, +2, +4 and +6. The well known halides are S 2 X 2 (X=F,Cl,Br or I) = oxidation state of S is +1 SX 2 (X=F or Cl) = oxidation state of S is +2 Sulphur hexaflouride (SF6) The oxidation state of Sulphur (s) in Sulphur hexaflouride ( SF 6 ) is +6. Sulphur hexaflouride (SF6) is prepared by direct combination of Sulphur (S) and Flourine (F). 1/8 S 8   +  3F 2   ----------->  SF 6 Sulphur hexaflouride ( SF 6 ) has octahedral shape. Sulphur atom is Sp 3 d 2 hybridised. Sulfur tetrafluoride (SF4) Sulfur tetrafluoride (SF4) is prepared by fluorination of SCl 2 with NaF 3SCl 2   +  4 NaF  ------------>  S 2 Cl 2   +  SF 4   +  4 NaCl Sulphur atom is  Sp 3 d hybridized in SF 4 and possess triagonal bipyramidal geometry with one corner is occupied by ...

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...

Trends in chemical reactivity of group 16 elements 1. The metallic character increases as we descend the group. Oxygen and sulphur are typical nonmetals. Selenium (Se) and Te are metalloids and are semiconductors. Polonium is a metal. 2. Tendency to form multiple bond decreases down the group. Example O=C=O is stable, S=C=C is moderately stable, Se=C=Se decomposes readily and Te=C=Te is not formed. 3. Formation of Hydrides All the elements of group 16 form hydrides of the type H 2 M (where M=O,S,Se,Te or Po). The stability of hydrides decreases as we go down the group. Except H 2 O, all other hydrides are poisonous foul smelling gases. Their acidic character and reducing nature increases down the group. All these hydrides have angular structure and the central atom is in sp 3 hybridisation. 4. Formation of Halides Element of group 16 form a large number of halides. The compounds of oxygen with fluorine are called oxyfluorides because fluorine is more electronegative than oxygen (...

Chemical properties of Group 15 elements 1. Phosphorous exhibit covalent character though it can accept three electrons to form phosphides. The covalent character decreases as we move down the group. that is Phosphorus (P) > Arsenic (As) > Antimony (Sb) > Bismuth (Bi) 2. Group 15 element Forming Hydrides The element of group 15 form hydrides of the type MH 3 . They are NH 3 (Ammonia), PH 3 (Phosphine), AsH 3 (Arsine), SbH 3 (Stibine) and BiH 3 (Bismuthine). Hydrides are covalent and central atom is sp 3 hybridized. Due to the presence of lone pair on central atom, they act as lewis bases and has pyramidal shape. The basic strength of hydrides decreases down the group. Thermal stability of hydrides also decreases on moving down the group. Except NH 3 all the hydrides are strong reducing agents and react with metal ions. The reducing character increases in going from NH 3 to BiH 3 . 3. Group 15 element Forming Halides The group 15 elements form two series of halides of...

Chemical properties of Group 14 elements 1. The elements of group 14 form covalent hydrides of the type MH 4 . The number of hydrides, their thermal stability and their ease of formation decreases as we move down the group. The reducing power of hydrides increases as we move from CH 4 to PbH 4 . Carbon forms a large number of cyclic and acyclic hydrides known as hydro carbons. Si andGe form hydrides of the formula M n H 2n+2 (where M=si, n=1 to 8; M=Ge, n=1 to 5). The hybrides of silicon are called silanes while those of Germanium are called Germanes. Tin and Lead from one hydride each, ie SnH 4 (Stannane) and PbH 4 (Plumbane). 2. Elements of Group 14 form two types of halides, tetrahalides (MX 4 ) and dihalides (MX 2 ) The tetrahalides are covalent and have tetrahedral geometry. Their thermal stability decreases down the group. The tetrahalides of group 14 except that of carbon are readily hydrolysed. SiCl 4 + 4H 2 O -----------> Si(OH) 4 + 4 HCl In carbon there is no vacant...

The important trends observed in the chemical behavior of group 13 elements are 1. Group 13 elements form hydrides of the type MH 3 . Thermal stability of hydrides decreases as we move down the group. Hydrides act as weak lewis acids. Boron forms a number of hydrides known as boranes. The important series among boranes are nido-boranes (B n H n+4 ) and arachno-boranes (B n H n+6 ). Aluminium and Galium can form tetra hydrido anions (MH 4 -).[LiAlH 4 ] is an example for this and is a good reducing agent used in organic synthesis. 2. The elements of group 13 form trihalides of the type MX 3 . The trihalides are strong Lewis acids. The flurides are ionic and have high melting points. The chlorides, bromides and iodides are covalent compounds with low melting points. Halides can exist in dimeric form with halogen bridges. 3. All the elements of group 13 form oxides with formula M 2 O 3 and hydroxides of the type M(OH) 3 . Basic character of oxides and hydroxides increases as we move down...

Trends of chemical properties in group 17 elements 1. Oxidizing property of halogens Group 17 elements are highly electronegative and hence they have strong tendency to accept electrons. Thus halogens act as strong oxidizing agents. F 2 is the strongest oxidizing halogen. A halogen can oxidizes halide ions of higher atomic number. F 2 + 2X - ----------> 2F - + X 2 [X = chlorine (Cl), Bromine (Br) or Iodine (I)] The oxidising ability of halogens decreases as we go down the Group. 2. Formation of Halides Halogens combine with metals, nonmetals and even noble gases to form halides. Metal halides are ionic and their ionic character decreases as M-F > M-Cl > M-Br > M-I Halogens combine with nonmetals and form covalent halides whose bond strength decreases as M-F > M-Cl > M-Br > M-I 3. Hydrides (Hydrogen halides) Halogens combine with hydrogen to form covalent halides of the type HX and are regarded as hydrides. Their acidic and reducing character increas...

Group 18 consists of the elements, helium, neon, argon, krypton, xenon, and radon, which are collectively known as noble gases. Due to their chemical inactivity they are also called inert gases. Occurrence and isolation Atmospheric air is the major source of noble gases. Radon is not found in atmosphere and is obtained as thee decay product of 226Ra. The total abundance of noble gases in dry air is approximately 1%. Neon, Argon, Krypton and Xenon are obtained by the liquefaction of dry air and separation of its constituents by fractional distillation. Helium is isolated from natural gas. When natural gas is compressed and liquefied, Helium remains along with unliquefied gas, which contains 2% nitrogen as impurity. N2 is removed by adsorption on charcoal at – 1900C. Atomic and physical properties Electronic configuration Except Helium, all other noble gases have ns2np6 configuration. The electronic configuration of He is IS2. Due to this stable electronic configuration, they have less t...

The oxyacids of chlorine are HCLO (Hypochlorous acid), HCLO2 (Chlorous acid), HCLO3 (Chloric acid) and HCLO4 (Perchloric acid). 1. Hypochloric acid or chloric(1)acid (HCLO) It is formed by passing chlorine gas through water. Cl2(g) + H2O (l) ----------> Na2SO4(aq) + 2 HCl (aq) 2. Chlorous acid or chloric (3)acid (HClO2) It is prepared by treating barium chlorate with sulphuric acid. Ba(ClO2)2 + H2SO4 -----------> 2HClO2 + BaSO4 3. Chloric acid or chloric(5)acid (HClO4) Perchloric acid is prepared by treating barium perchlorate with sulphuric acid. Ba(ClO4)2 + H2SO4 ------------> 2HClO3 + BaSO4 4. Perchloric acid or chloric (6) acid Perchloric acid is prepared by treating barium perchlorate with sulphuric acid. Ba(ClO4)2 + H2SO4 -----------> 2HClO4 + BaSO4 For List of oxyacids visit (picture) oxyacids of chlorine For Other examples of oxyacid visit oxyacids of phosphorous

In the laboratory phosphine is prepared by heating white phosphorus with concentrated caustic alkali solution in an inert atmosphere of oil gas or CO2. P4 + 3NaOH + 3H2O ------------> 3NaH2PO2 (Sodium hypophosphite) + PH3 (phosphine) Metal phosphides on hydrolysis form phosphine Ca3P2 + 6H2O ------------> 3Ca(OH)2 + 2PH3 A pure sample of phosphine can also be prepared by heating phosphorous acid 4H3PO3 ---------------> 3H3PO4 + PH3 Phosphine has pyramidal structure and is a weaker base than NH3

The main oxides of phosphorus are phosphorus trioxide (P4O6) and phosphorus pentoxide (P4O10) . Phosphorous trioxide is regarded as the anhydride of phosphorous acid (H3PO4). phosphorus trioxide (P4O6) is prepared by heating phosphorous in limited supply of oxygen. P4O10 is prepared by burning white phosphorous in excess of air or oxygen. P4 + 3O2 -------------> P4O6 P4 + 5 O2 ------------> P4O10 P4O10 has great affinity for water and hence it is used as a dehydrating agent. It can dehydrate HNO3 and H2SO4 to yield N2O5 and SO3 respectively. 2H2SO4 + P4O10 ------------> 2SO3 + 4HPO3 P4O6 and P4O10 dissolves in water to give phosphorus acid and orthophosphoric acid respectively. P4O6 + 6H2O -------------> 4H3PO3 P4O10 + 6H2O --------------> 4H3PO4 Related article oxyacids of phosphorus

Xenon trioxide (XeO3) XeO3 prepared by the slow hydrolysis of XeF6 XeF6 + 3H2O ------------> XeO3 + 6HF Xenon trioxide is soluble in water and its aqueous solution is weakly acidic. XeO3 + H2O <--------> H+ + HXeO4 – Xenate ion XeO3 has pyramidal structrure in which Xe is in sp3 hybridisation. Xenon tetroxide (XeO4) It is prepared by treating barium perxenate (Ba2XeO6) with anhydrous sulphuric acid. Ba2XeO6 + 2H2SO4 -----------> XeO4 + 2BaSO4 + 2H2O Xenon tetroxide is highly unstable and has tetrahedral structure. Related article fluorides of xenon For more detail visit indiastudychannel.com

Hydrogen sulphide is prepared in laboratory by the action of dilute HCl or dilute H2SO4 on ferrous sulphide in Kipp’s apparatus. FeS + H2SO4 ---------->4 + H2S Physical properties It is colourless gas with the smell of rotten eggs. It is denser than air and is soluble in water. Chemical properties 1. Combustibility Hydrogen sulphide burns in limited supply of oxygen to form sulphur. In presence of excess of oxygen, it gives sulphur dioxide. 2. Acidic property H2S is a weak dibasic acid and forms two types of salts namely bisulphides and sulphides NaOH + H2S ----------> NaHS + H2O 2NaOH + H2S ----------> Na2S + 2H2O 3. Action with metals When H2S is passed over hot metals the sulphides and hydrogen are formed Cu + H2S -----------> CuS + H2 4. Hydrogen sulphide in qualitative analysis H2S precipitates metal sulphides having characteristic colours from metal salt solutions in acidic or alkaline medium. Therefore H2S is used in qualitative analysis to identify metal ions belong...

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It is prepared by boiling sulphur with an aqueous solution of sodium sulphate Na2SO3 + 1/8 S8 ------> Na2S2O3 Properties Sodium thiosulphate is a water soluble crystalline substance. a) Reaction with iodine Sodium thiosulphate is oxidised by iodine to form sodium tetra thionate. This reaction is the basis of iodometric titrations. 2Na2S2O3 + I2 ---------> Na2S4O6 + 2NaI b) Reaction with chlorine Sodium thiosulphate can remove excess chlorine by forming HCl. Hence it is used as an antichlor. Na2S2O3 + Cl2 + H2O -----------> Na2SO4 + 2HCl + S c) Reaction with silver halides Silver halides dissolve in sodium thiosulphate solution due to formation of a complex sodium argento thiosulphate. This reaction is the basis of its use in photography as fixer. AgCl + Na2S2O3 -------------> NaAgS2O3 + NaCl

The stable oxides of sulphur are sulphur dioxide (SO2) and sulphur trioxide (SO3) Sulphur when burnt in air form sulphur dioxide. S8 + 8O2 -------------> 8SO2 SO2 is a gas at room temperature. It exists as descrete SO2 molecule with angular structure. SO3 is an acidic oxide and exist as planar triangular molecule in gas phase. In solid state, SO3 exist either as cyclic trimer or linear chain polymer.