Inorganic Chemistry: Metallurgy Suggestion PDF

# Inorganic Chemistry: Metallurgy ## 1. Difference: ### Roasting: - Ore is heated in the presence of oxygen. - Applicable for sulfide or those ores in which oxygen is absent. - Water is not eliminated. **Example:** - 2ZnS + 3O₂ → 2ZnO + 2SO₂ - 2PbS + 3O₂ → 2PbO...

# Inorganic Chemistry: Metallurgy ## 1. Difference: ### Roasting: - Ore is heated in the presence of oxygen. - Applicable for sulfide or those ores in which oxygen is absent. - Water is not eliminated. **Example:** - 2ZnS + 3O₂ → 2ZnO + 2SO₂ - 2PbS + 3O₂ → 2PbO + 2SO₂ ### Calcination: - Ore is heated in the absence of oxygen. - Applicable for carbonate or hydrated ores. - Water molecules are eliminated in this process. **Example:** - Al₂ O₃ . 2H₂O → Al₂O₃ + 2H₂O - Fe₂O₃ . 7H₂O → Fe₂O₃ + 7H₂O ## 2. Define: ### Gangue: - The undesirable impurities present in ores are called gangue or matrix. - **Example:** SiO₂ (Silica), water, other metals. ### Flux: - Substances which mix with gangue to form a new substance are called flux. - **Example:** CaO etc. ### Slag: - The new substance formed by mixing gangue with flux is called slag. - **Example:** SiO₂ + CaO → Calcium silicate (CaSiO₃) # Extraction of Aluminium "Bayer’s Process" - The main ore of Al is Bauxite (Al₂O₃ . 2H₂O) and cryolite (Na₃ AlF₆). - Aluminium is extracted from Bauxite by Bayer's method. It is a method of leaching. - In this process, impure Bauxite is mixed with an alkaline solution of NaOH. - The ore is dissolved in it to form sodium metaaluminate and impurities are left behind. - Al₂O₃ . 2H₂O + 2NaOH → 2NaAlO₂ + 2H₂O - The obtained solution is then neutralized by heating with water. - NaAlO₂ + 2H₂O → Al(OH)₃ + NaOH - Al(OH)₃ is heated at 1200 °C to form pure alumina. - 2Al(OH)₃ → Al₂O₃ + 3H₂O ## Hall Process of Leaching: - Impure Bauxite is mixed with Na₂CO₃. - Then Bauxite is leached to form sodium metaaluminate. - The solution is filtered and then neutralized by passing CO₂ in this solution at 50-60 °C. - Al(OH)₃ is obtained which is heated to form pure alumina. - Al₂O₃ . 2H₂O + Na₂CO₃ → 2NaAlO₂ + CO₂ + 2H₂O - NaAlO₂ + CO₂ + 3H₂O → 2Al(OH)₃ + Na₂CO₃ - 2Al(OH)₃ → Al₂O₃ + 3H₂O ## Electrolytic Refining of Aluminium: - This process uses a carbon anode and a carbon cathode. - The electrolytic bath contains Al₂O₃ + Na₃AlF₆ - Molten aluminium is collected at the bottom of the cell. ## The processes involved are: - **Ionization of Alumina:** - 2Al₂O₃ → 4Al³⁺ + 6O^2- - **Reaction at Cathode:** - 4Al³⁺ + 12e^- → 4Al (Pure aluminium) - **Reaction at Anode:** - 6O^2- → 3O₂ + 12e^- - C → 3O₂ # Extraction of Iron - The main ore of iron are: - Hematite - Fe₂O₃ - Limonite - Fe₂O₃.xH₂O - Magnetite - Fe₃O₄ - Iron is extracted industrially from Hematite ore. ## The Steps Involved: - **Concentration of Hematite ore:** Impurities like water and other volatile compounds are removed from the ores. - **Roasting:** The ore is roasted in a furnace and then it is smelted. - **Smelting:** Smelting of hematite takes place in the blast furnace. It involves some steps: - **Loading:** The concentrated ores, limestone and coke are loaded into the top of the blast furnace. - **Preheated air is injected at the bottom of the furnace.** - **Reactions:** - The limestone decomposes into calcium oxide, which reacts with silicon dioxide to form a slag. - The hematite reacts with carbon to produce pure iron and carbon monoxide gas. - **Temperature (K)** | **Reaction** ---|--- 700K | Reduction begins. 3Fe₂O₃ + CO → 2Fe₃O₄ + CO₂ 875K | 1070K | CaCO₃ → CaO + CO₂ 1270K | CaO + SiO₂ → CaSiO₂ (Slag) 1570K | Fe₂O₄ + CO→ 2FeO + CO₂, C + CO₂ → 2CO, C + O₂ → CO₂. Carbon burns. 2170K | FeO + C → Fe + CO - **Molten iron is collected at the bottom of the furnace and slag is removed from the top.** # Chapter: The p-block elements ## 1. Nitrogen can form only N₂ but phosphorus can form both P₂ and P₄. Why? - **Answer:** Phosphorus has a vacant d-orbital in its outermost orbit so phosphorus can form P₂ and P₄ both. But Nitrogen have no d-orbital in its orbit due to which it can only form N₂. ## 2. Structures of oxoacids of phosphorus and P-O-P bonds **1. Hypophosphorous acid (phosphinic acid) - H₃PO₂:** - Structure: A central phosphorus atom bonded to two hydrogen atoms, one hydroxyl group, and one oxygen atom. - P-O-P bond: P-O-P=0 **2. Orthophosphorous acid (H₃PO₃):** - Structure: A central phosphorus atom bonded to two hydrogen atoms, one hydroxyl group, and one oxygen atom. - P-O-P bond: P-O-P = 0 **3. Pyrophosphorous acid (H₄P₂O₅):** - Structure: Two phosphorus atoms bonded to each other with a P-O-P bond, each phosphorus atom is also bonded to two hydroxyl groups and one hydrogen atom. - P-O-P bond: P-O-P = 1 **4. Hypophosphoric acid (H₄P₂O₆):** - Structure: Two phosphorus atoms bonded to each other with a P-O-P bond, each phosphorus atom is also bonded to one hydroxyl group, and one hydrogen atom. - P-O-P bond: P-O-P=0 **5. Orthophosphoric acid (H₃PO₄):** - Structure: A central phosphorus atom bonded to three hydroxyl groups and one oxygen atom. - P-O-P bond: P-O-P = 0 **6. Pyrophosphoric acid (H₄P₂O₇):** - Structure: Two phosphorus atoms bonded to each other with a P-O-P bond, each phosphorus atom is also bonded to two hydroxyl groups and one hydrogen atom. - P-O-P bond: P-O-P = 1 **7. Metaphosphoric acid (HPO₃)_n:** - Structure: A chain of phosphorus atoms, each bonded to two oxygen atoms and one hydroxyl group. - P-O-P bond: Not applicable for the general formula. ## 8. Preparation of NH₃ - **Methods:** - NH₄Cl + H₂O → (NH₄)₂CO₃ + NH₃↑ + H₂O + CO₂ (Ammonium carbonate) - NH₄Cl + Ca(OH)₂ → CaCl₂ + H₂O + NH₃↑ - (NH₄)₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O + 2NH₃↑ - **On a large scale, NH₃ is prepared by Haber's process:** - N₂(g) + 3H₂(g) → 2NH₃(g) ΔH⁰ = -46.1 kJmol (Exothermic) - **According to Le Chatelier’s principle, some conditions should be applied to this reaction for max yielding of ammonia:** - **High pressure (200 atm) and low temperature (≈ 400K).** - **Catalyst applied in the form of iron oxide with a small amount of Al₂O₃** ## Properties of NH₃ - **Physical properties:** - Colourless, smell gas with a pungent smell. - F.P = -198.4 K, B.P = -239.7 K. - It is associated with H-bonding in solid and liquid state. - In water, it forms NH₄OH. - It can be easily liquefied due to high P.C. - **Chemical Properties:** - **Basic in nature**: It works as Lewis base. - 2NH₃ + H₂SO₄ → (NH₄)₂SO₄ (Ammonium sulphate) (It’s a weak base) - **Due to the presence of a lone pair on the N-atom, it can form co-ordinate bonds.** - NH₃ + Cu²⁺ → [Cu(NH₃)₄]²⁺ - Ag⁺ + Cl^- → AgCl (insoluble with H₂O) - AgCl + NH₃ → [Ag(NH₃)₂]⁺ + Cl^- ## Uses of NH₃ - Used to prepare nitrogenous fertilisers (NH₄NO₃, (NH₄)₃PO₄, etc). - Used to prepare HNO₃/refrigeration. # Preparation of H₂SO₄ (Contact Process): - This process involves three basic steps: - **Step 1: Formation of SO₂ gas by burning sulfur or sulfide ores:** - S + O₂ → SO₂(g) - 2ZnS + 3O₂ → 2ZnO + 2SO₂(g) (Impure arsenides) - **Step 2: Conversion of SO₂ into SO₃:** - 2SO₂(g) + O₂ → 2SO₃(g) ΔH = -196.6 kJmol - Since the reaction is exothermic and volume decreases during sk, so lower temp and high pressure are favourable conditions for better yield. - **Step 3: Absorption of SO₃ on impure H₂SO₄:** - SO₃ + H₂SO₄ → H₂S₂O₇ (Oleum) - H₂S₂O₇ + H₂O → 2H₂SO₄ (98-99% pure) ## Properties of H₂SO₄: - Colourless, dense, oily liquid. - Specific gravity = 1.84 at 298 K. - B.P = 611K. - Dissolve in water (exothermic). - **Ionisation in water:** - H₂SO₄ + H₂O → H₃O⁺ + HSO₄^- (K_a1D) - HSO₄^- + H₂O → H₃O⁺ + SO₄^2- - **Dehydrating in nature:** - C₁₂H₂₂O₁₁ + H₂SO₄ → 12C + 11H₂O # Preparation of HNO3 (Nitric acid): - **Lab Method:** 2NaNO₃ + H₂SO₄ → Na₂SO₄ + 2HNO₃ - **Industrial Method (Ostwald’s Process):** - **Step 1:** 4NH₃(g) + 5O₂(g) → Pt-Rh gauze catalyst 4NO(g) + 6H₂O (500K, 4 bar) (Nitric oxide) - **Step 2:** 2NO(g) + O₂(g) → 2NO₂ (g) (Nitrogen dioxide) - **Step 3:** NO₂(g) + H₂O(l) → HNO₃ + NO(g) (small) - Aq HNO₃ can be concentrated up to 68% by mass by further distillation, it can be concentrated up to 98% by mass by applying conc. H₂SO₄ as a dehydrating agent. ## Physical Properties of HNO₃: - It is a colourless liquid (in pure state). - Impure acid is yellow due to the presence of nitrogen dioxide as impurity. - B.P = 355.6K - F.P = 231.4K - It is corrosive in nature. ## Chemical Properties of HNO₃: - **Acidic in nature:** - HNO₃ + H₂O → H₃O⁺ + NO₃^- - **Action on metals:** - Conc. HNO₃ + Zn(s) → Zn(NO₃)₂ + H₂O + NO₂ - Dil. HNO₃ + Zn(s) → Zn(NO₃)₂ + H₂O + N₂O - Cr, Al can’t dissolve in HNO₃ - **Aqua-Regia:** Conc. HNO₃ + Conc. HCl ## Uses of HNO₃: - TNT (Trinitrotoluene) - It is used to manufacture other fertilizers. - Formation of TNT and picric acid. - In purification of gold, silver in the form of Aqua Regia. - Used as an oxidizer in rocket fuel. # Preparation of Cl₂: - Chlorine is prepared by oxidation of hydrogen chloride gas by atmospheric oxygen in the presence of CuCl₂ at 723K. - This method is called Deacon’s process. - 4HCl(g) + O₂ → CuCl₂ >2Cl₂ + 2H₂O ## Properties of Cl₂: - **Colour:** Yellow-green - **Smell:** Strong pungent smell, similar to bleach. - **Melting point:** -10°C # Preparation of O₃ (Ozone): - **Preparation of ozone:** 3O₂ (Silent discharge) → 2O₃ (10%) - **When a slow stream of O₂ is passed through a silent electrical discharge, then 10% of O₂ is converted into ozone.** - It is also called ozonoid oxygen. - For more yield, ozoniser is used. - B.P = 101.1K ## Properties of Ozone: - **Physical:** - Pale blue gas, dark blue liquid and violet black solid. - Has a characteristic smell. - Harmful above 1000 ppm in intake. - **Chemical:** - It is thermodynamically unstable. - Due to liberation of nascent oxygen, it behaves as a strong oxidizing agent. - PbS + 4O₃ → PbSO₄ + 4O₂ - It rapidly reacts with NO to convert NO and O₂. - O₃ + NO → NO₂ + O₂ - It is affected by the uses of CFCs. (Freon (CF₂Cl₂)) ## Uses of Ozone: - Germicides, disinfectants etc. - Bleaching of oil, flour etc. - Preparation of Potassium permanganate (KMnO₄ ) ## Occurrence of I₂ in seaweeds: - Iodine (I₂) occurs in seaweeds. - Iodide (I-) taken by seaweeds reacts with atmospheric ozone. - This reaction happens when seaweeds are uncovered and stressed at low tide. - Seaweeds are a valuable source of iodine but some types of brown seaweed can contain high levels of iodine which may be harmful to health. # Structure of KrF₂, XeF₄, XeF₆: - **KrF₂:** - :F-Kr-F: - **XeF₄:** - Structure of XeF₄: - Xe is central atom, surrounded by four fluorines and - two lone pairs of electrons - Shape: Square planar - **XeF₆:** - Structure of XeF₆: - Xe is central atom, surrounded by six fluorines and - one lone pair of electrons - Shape: Distorted octahedral # Chapter: d and f block elements ## 1. General Electronic Configuration of d and f block elements. ### d-block: - General configuration: ns^1-2 (n-1)d^1-10 ### f-block: - General configuration: ns² (n-1)d^0-1 (n-2)f^1-14 ## 2. Define Transition Metal: - The metal of d- block element which have atleast an unpaired electron in their d-subshell are called transition metal. - **Example:** ₂₆Fe⁺²: [Ar] 4s⁰ 3d⁶ ## 3. Oxidation state of d-block elements (Sc-Zn): - Sc: +3 (Most stable) - Ti: +2, +3, +4 - V: +2, +3, +4, +5 - Cr: +1, +2, +3, +4, +5, +6 (Most stable) - Mn: +2, +3, +4, +5, +6, +7 (Most stable) - Fe: +2, +3, +4, +5, +6 - Co: +2, +3, +4, +5 - Ni: +2, +3, +4 - Cu: +1, +2, +3 - Zn: +2 (Most stable) ## 4. Lanthanide Contraction: - When atomic radius decreases on increasing atomic number, due to increase in nuclear charge, it’s called Lanthanide/Actinide contraction. ## 5. Why the compounds of transition metals shows colour? - The compounds of transition metals shows colour because there are partially filled d-orbitals. - This allows electrons to be easily excited to higher energy levels when visible light is absorbed, leading to a specific wavelength of light being absorbed and the complementary colour being transmitted. - This process is called d-d transition. ## 6. Define Diamagnetism and Paramagnetism by spin only formula. - **Diamagnetism:** Those substances which are repelled by a magnetic field are called diamagnetic substances and this phenomenon is called diamagnetism. - **Paramagnetism:** Those substances which are attracted by a magnetic field are called paramagnetic substances. Such phenomenon is called paramagnetism. - **Explanation:** - **Diamagnetism:** They do not have unpaired electrons in their atomic orbitals. - **Paramagnetism:** They have some atomic unpaired electrons in their atomic orbitals.  **Example:** - **Diamagnetic:** ₂₀Ca⁺² : [Ar] 3d⁰ - n = 0 (number of unpaired electrons) - μ = √n(n+2) = √0(0+2) = 0 - **Paramagnetic:** ₂₆Fe⁺² : [Ar] 3d⁶ - n = 4 (number of unpaired electrons) - μ = √n(n+2) = √4(4+2) = √24 = 2√6 BM # Chapter: Co-ordination Compound ## 1. IUPAC Naming: - **Counter metal** + **(C.N of metal) + (ligands) + (C.N of counter ion)** - **Example:** K₂[Fe(CN)₆] - **Counter metal:** Potassium - **Central Metal:** Iron - **Ligand:** Cyanido - **Coordination number of Fe:** 6 - **Coordination number of K:** 2 - **Counter ion:** None - **Name:** Potassium hexacyanidoferrate(II) ## 5.1 Write the formula for the following co-ordination compounds: - **1. Tetraammine diaquacobalt(III) chloride:** [Co(NH₃)₄(H₂O)₂]Cl₃ - **2. Potassium tetracyanidonickelate (II):** K₂[Ni(CN)₄].  - **3. Tris(ethane-1,2-diamine)chromium (III) chloride:** [Cr(en)₃]Cl₃ - **4. Amminebromidochloridonitrito-N-platinate(II):** [Pt(NH₃)BrClNO₂] - **5. Dichloride bis(ethane-1,2-diamine)platinum(IV) nitrate:** [Pt(en)₂Cl₂](NO₃)₂ - **6. Iron(III) hexacyanidoferrate(II):** Fe₄[Fe(CN)₆]₃ ## 5.2 Write IUPAC names for the following co-ordination compounds: - **1. [Co(NH₃)₆]Cl₃:** Hexaamine cobalt (III) trichloride - **2. [Co(NH₃)₅Cl]Cl₂:** Pentaamminechlorido cobalt (III) dichloride ## 5.3 Write the formula for the following complex ions: - **1. Tetrahydroxidozincate(II):** [Zn(OH)₄]^2- - **2. Potassium tetrachloridopalladate (II):** K₂[PdCl₄] - **3. Diamminedichloridoplatinum (II):** [Pt(NH₃)₂Cl₂] - **4. Potassium tetracyanidonickelate (II):** K₂[Ni(CN)₄] - **5. Pentaamminenitrito-O-cobalt (III):** [Co(NH₃)₅ONO] - **6. Hexaammine cobalt (III) sulphate:** [Co(NH₃)₆]SO₄ - **7. Potassium hexalato chromate (III):** K₃[Cr(C₂O₄)₃] - **8. Hexaammineplatinum (IV):** [Pt(NH₃)₆]⁴⁺ - **9. Tetrabromidocuprate (II):** [CuBr₄]^2- - **10. Pentaamminenitrito-N-cobalt (III):** [Co(NH₃)₅NO₂] ## **5.5 Determine the oxidation states of the central metals in the following complex compounds:** - **1. [Co(H₂O)(en)(en)₂]²⁺:** - Let the oxidation state of Co be x. - x + (0+1x2) + (+2x2) =+2 - x + 2+4 = 2 - x = -4 - x= +2 - **2. [CoBr₄]^2-:** - Let the oxidation state of Co be x. - x + (-1x4) = -2 - x - 4 = -2 - x = +2 - **3. [Cr(NH₃)₃Cl₃]:** - Let the oxidation state of Cr be x. - x + 0 + (-1×3) = 0 - x - 3 = 0 - x = +3 - **4. [CoBr₂(en)₂]⁺:** - Let the oxidation state of Co be x. - x + (-1x2) + (2x2) = +1 - x - 2 + 4 = 1 - x = -1 - x = +3 - **5. [Co(en)₃]³⁺:** - Let the oxidation state of Co be x. - x + (0+1x2) + (2x2) = +3 - x + 4 = 3 - x = -1 - x = +3 ## **5.6 Write the formula for the following complex ions:** - **1. Tetrahydroxidozincate(II):** [Zn(OH)₄]^2- - **2. Potassium tetrachloridopalladate(II):** K₂[PdCl₄] - **3. Diamminedichloridoplatinum(II):** [Pt(NH₃)₂Cl₂] - **4. Potassium tetracyanidonickelate(II):** K₂[Ni(CN)₄] - **5. Pentaamminenitrito-O-cobalt(III):** [Co(NH₃)₅ONO] - **6. Hexaamminecobalt(III) sulphate:** [Co(NH₃)₆]SO₄ - **7. Potassium hexalatochromate(III):** K₃[Cr(C₂O₄)₃] - **8. Hexaammineplatinum(IV):** [Pt(NH₃)₆]⁴⁺ - **9. Tetrabromidocuprate(II):** [CuBr₄]^2- - **10. Pentaamminenitrito-N-cobalt(III):** [Co(NH₃)₅NO₂] ## 9. CFT in tetrahedral and octahedral complex - **CFT in tetrahedral complex:** - The energy of e_g increases by 2/5 Δ_t from the barrier and the energy of t_2g decreases by 3/5 Δ_t from the barrier. - **CFT in octahedral complex:** - The energy of e_g increases by 3/5 Δ_o from the barrier and the energy of t_2g decreases by 2/5 Δ_o from the barrier. ## 10. Oxidation State: - The oxidation state is the gain or loss of electrons in passing from a neutral atom to an ion carrying charge.  - It is also called an oxidation number. ## 11. Coordination Number: - The number of lone pairs donated by the ligands to the central metal atom in a complex is called coordination number. - It is fixed for a given metal atom. - **Example:** K₄[Fe(CN)₆] = C.N. of Fe = 6  ## 12. Effective Atomic Number (EAN): - The total number of electrons present in the orbitals of the central metal atom in a complex is called its EAN. - EAN= Atomic number of metal + 2 × C.N. - **Example:** K₄[Fe(CN)₆] - EAN = 26 + 2 × 6 - EAN = 36 [Xe] ## 13. Define Ambidentate Ligands: - A ligand which has two donor atoms but only one can donate lone pairs to the central metal atom is called an ambidentate ligand. - **Example:** NO₂, SCN, N₃, NCS, ONO, CN, NC etc. ## **14. Define Chelate:** - When the ligands form an enclosed structure with central metal ion, then it’s called a chelate. ## 15. Structure of EDTA: - EDTA means **Ethylenediaminetetraacetate ion.** - EDTA is a hexadentate ligand. It can donate six lone pairs of electrons to the central metal atom.  - Structure: The central atom of EDTA is a carbon atom, which is attached to two amino groups, two carboxyl groups, and two methylene groups. The two carboxyl groups at the ends of the molecule can donate their lone pairs of electrons to the central metal atom to form coordinate bonds. - Denticity = 6