INORGANIC QUESTIONS

1. By giving reasons, predict in each of the following pairs which ion is larger: (a) Mg2+ and Ca2+ (b) K+ and Ca2+ (c) Na+ and F- (d) Cu2+ and Cu+ 2. Briefly explain the following phenomena; (a) When SO2 is bubbled through acidified aqueous solution of potassium dichromate, K2Cr2O7, the yellow colour of the latter turns green. (b) Silver Chloride is insoluble in water but readily soluble in aqueous ammonia. (c) Iron (ii) solution is stored in copper vessel container but Copper (ii) solution cannot be stored in iron vessel container. (d) Lead (ii) Chloride is soluble in concentrated HCl but insoluble in dilute HCl. (e) Concentrated sulphuric acid is a drying agent but cannot be used to dry hydrogen sulphide gas 3. Explain the meaning of the following terms; (a) Paramagnetism (b) Coordination number (c) A ligand (d) Disproportionation reaction (e) Bidentate ligand. (f) Lone pair of electron. (g) Polarising power. (h) Polarizability (i) Catenation (j) Expansion of valence shell (k) Inert pair effect (l) Froth floatation (m) Metal ore. (n) Concentration of ore. (o) Chelating agent (p) Hybridization of atomic orbitals (q) Coordination compound (r) Ligand (s) Complex ion (t) Counter ion (u) Periodicity. (v) Screening effect. (w) Effective nuclear charge. (x) Neutral complex (y) Ionization isomerism. 4. (a) Write the electronic configuration of Cr3+, Cr and Cu and explain why Cr and Cu violet Aufbau principle. (b) Write down the formula of the following Chromium complex: “Dichlorobis(ethylenediamine)chromium(III) nitrate and then identify the anionic and neutral ligand from the complex. 5. Write the IUPAC names of the following complexes and state the coordination number of each central atom. (a) [Pt(NH3)3C2O4Cl]Cl (b) K[Au(CN)2] (c) [Co(NH3)5Br]SO4 (d) [ Co(CO)4]+ 6. Explain un ionic terms, the following facts with the help of a chemical equation where necessary (a) Silver chloride is almost insoluble in water but dissolves readily into solution when excess ammonia is added. (b) Iodine is readily soluble in a concentrated solution of potassium iodide but only sparingly soluble in water. (c) The addition of potassium cyanide solution to a solution of silver nitrate given a white precipitate which the dissolves in excess of potassium cyanide. (d) Bromine has more electron affinity than although they belong to the same group. (e) The atomic radius of strontium in group 2 is larger than that of magnesium in group 2 (f) An hydrous aluminum chloride does not conduct electricity but is its aqueous does. (g) An aqueous solution of aluminum chloride turns blue litmus paper red. (h) A white precipitate tend to be formed, dissolves when carbondioxide is bubbled till excess through calcium hydroxide solution. 7. Give explanation of the following (use chemical equation where necessary). (a) Aluminium metal does not react with hot water or stem. (b) F2 and Cl2 exist gases Br2 exists in the liquid form while, I2 exist as solid. (c) Lithium carbonate is easily decomposed thermally compared with sodium carbonate. (d) Sodium metal is very soft compared with magnesium metal (e) Silicon tetrachloride (SiCl4) can be hydrolyzed by water, but carbon tetrachloride (CCl4) cannot. (f) Only lithium reacts with nitrogen to form nitride in group one. (g) Group IV elements have in common the +2 and +4 oxidation states. (h) Group three elements largely show covalency (i) Nitrogen and phosphorus are non metals, arsenic and antimony are metalloids (semi-metal), and bismuth is a true metal. (j) Although it is hard to have  3 Al ,  Al H O   3 6 is stable. At the same is difficult to 2 find   B H O   3 6 2 (k) The first ionization energies show a general increase from sodium to chlorine 8. (a) State four properties of diagonal relationship between Be and Al (b) (i) State the modern period law (ii) What are the two factors to classify the elements in the periodic table? (c) Define the following (i) Electron affinity (ii) Electronegativity (iii) Ionization energy 9. By using chemical equations, explain how Aluminium is extracted from Bauxite. 10. Explain the following (a) Sodium is less reactive than potassium (b) Sodium atom is large in size than aluminium atom (c) Sodium compounds are more ionic than that Magnesium compounds. (d) Sodium ion is smaller than sodium atom . (e) A chlorine ion is large in size than chlorine atom. (f) Chlorine is a strong oxidizing agent than iodine though are in the same group. (g) Electron affinity of elements decrease down the groups of the periodic table but the electron affinity of chlorine is higher than that of fluorine (h) Group VII elements have the highest electronegativity value while group 1 elements has the lowest. (i) Reducing ability of group 1 elements increases as the group descended (j) Aluninium chlorine is a Lowes acid. (k) Aluminium ore is first dissolved in cryolite before it is electrolyzed 11. (a) Briefly explain the term diagonal relationship. (b) Explain the differences between graphite and diamond basing on the following properties (i) Hardness (ii) Electrical and thermal conductivity (iii) Lubricating qualities 12. Explain the effect of hydrogen bonding on the boiling point and solubility of a compound 13. Concentrated sulphuric acid should not be used to dry hydrogen sulphide. Explain 14 Briefly explain the following terms;- (a) Beryllium halides exist in dimmers in the vapour phase while calcium halides in the same group exist inmonomers. (b) Fluorine does not dissolve in water to form hypohalous acid like chlorine (c) Alkali metals are good reducing agents. (d) Common chemical reducing have no action on aluminium are (e) BF3 is Lewis acid (f) BF3 non polar but NH3 is polar. (g) Aluminium fluoride has much high melting point than aluminium chloride (h) Alkaline metals are not involved in complex compound formation (i) Alkaline metals does not occur uncombined in nature (j) A solution of ammonium ethanoate has a H P of 7 (k) Potassium ion (K  ) is smaller than chlorine ion   Cl  through 15. With the aid of well labelled diagram describe how iron is extracted from its haematite ore. 16. (a) Give the oxidation state and coordination number of the central metal atoms in the following complexes. (i) K3 [Co(C2O4)2] (ii) (NH4)2 [CoF6] (iii) [Mn(H2O)6]SO4 (iv) [Cr(en)2Cl2]Cl (b) Write the IUPAC names of the coordination compounds in 6 (a) above. 17. Explain the following observations;- (a) When potassium permanganate is used I volumetric analysis it is acidified using dilute sulphuric acid but not dilute hydrochloric acid or nitric acid (b) Aqueous sodium hydroxide absorbs carbon dioxide readily but it is never used to test the gas. (c) Nitric acid can be stored aluminium tanks but it is sulphuric acid or sodium hydroxide (d) Silicon has a much higher melting point than it is expected (e) Graphite is used as a lubricant as well as cell electrode but not diamond (f) The first ionization energy of oxygen is lower than that of nitrogen although oxygen is towards the right across period two in the periodic table. (g) Carbon dioxide is a gas at room temperature while silicon dioxide is solid (h) Calcium carbonate is insoluble in water but dissolve in presence of dissolved carbon dioxide. (i) While the pentavalent compounds of nitrogen do not exist. 19. (a) Explain briefly how the oxide ores are reduced in the process of metal extraction. (b) What is the difference between;- (i) Calcination and roasting of metal ores. (ii) Ore and mineral. (c) With the aid of well balanced chemical equations ,explain how tin is extracted from its Ore (d) Discuss the environment effect of extraction metals and their remedial measures. 20. (a) Give evidence that [Co(NH3)5Cl]SO4 and [Co(NH3)5SO4 ]Cl are ionization isomers. (b) Draw the structures of the following compounds. (i) Hexaamminecolbalt(III) chloride. (ii) Bromopentaaquamanganese(III)sulphate. (iii) Potassiumtrisoxalatoferrate(III). (iv) Chlorodiamminemethylammineplatinum(II) chloride. 21. (a) Justify the classification of manganese as a catalyst. (b) Give the type of hybridization of [Fe(CN)6]-4 and draw the geometrical structure of the complex ion. 22. Explain the following;- (a) Aluminium is more metallic than boron through both or found in group III of the periodic Table. (b) Some compounds of lithium have a partially covalent character (c) Whereas carbon forms a limitless number of stable hydrides, this tendency (d) Although water and hydrogen shlphide are the hydrides of the elements of the same group, boiling point of water is higher than of hydrogen sulphide (e) Iodine and chlorine both are found in group seven of the periodic table but hydrogen iodide is a stronger reducing agent than hydrogen chloride (f) Hydrogen iodide does not form hydrogen bonding while hydrogen fluoride does although both are hydrides of group seven. 2 (g) The size of  Na ion is large than of Mg ion although both have the same number of electrons 23 . (a) Compare and contrast the arrangement of elements in Mendeléev’s Periodic Table and the Modern Periodic Table. (b) Study the variation in the first ionization of elements across period 2 and 3 and then answer the questions that follow;- ergyn e ion izat Ion 5 10 15 20 Atomic numbers. (i) Explain why argon has higher first ionization energy than the other elements in period 3. (ii) Explain why Boron has lower first ionization energy than Beryllium? (iii) How would the tendency to gain and loosing electrons change as you go from left to right across a period 3?Give reasons to support your answer. (iv) Arrange the period 3 element in order of increasing atomic size. 24. With the aid of chemical equation where necessary ,explain the following;- (a) Aluminium carbonate does not exist. (b) Aqueous solution of Fe3+ is acidic. (c) When ammonium solution is added to into aqueous of Cu2+ ions, pale blue precipitate will appear ,but these will dissolve in excess of alkali to form a deep blue solution. (d) Silver nitrate may react with the compound [Pt(NH3)3Cl3]Cl but not with the compound [Pt(NH3)2Cl4]. 25. Explain why Iron (Fe) ;- (a) is ferromagnetic. (b) Conducts heat and electricity. (c) Exhibit variable oxidation states. (d) Is used as catalyst a catalyst in hydrogenation of unsaturated hydrocarbons. 26. (a) Give explanation on the following. (i) Compounds containing the Zn2+ are colourless while those containing Cr3+ are Coloured. (ii) Co(CN)6]3- is yellow while [Co(NH3)6]3+ is green. (b) Consider the complex compound of the formula [Cu(H2O)6] [ Fe(CN)6] (i) What are central metal atoms? (ii) What is anionic complex in the compound? (iii) What are oxidation states of the central metal atoms? (iv) Write the name of the compound .. (c) Write the IUPAC names of the following compounds. (i) K [Al(OH)4] (ii) [Co (NH3)3(H2O)2Br](NO3)2 (iii) [Ni(CN)5]3- (iv) [Cr(H2O)5Cl]Cl2.H2O. 27. (a) Give reasons for the following (i) Transition metal ions form complexes. (ii) Transition metal salts are generally coloured (iii) Transition elements have high enthalapy of hydration (iv) Transition metals form alloys. (b) [Co(NH3)5Br]SO4 and [Co(NH3)5SO4]Br are isomers (i) Which ions will these isomers yield in solution? (ii) What is the coordination number of cobalt in each isomer? (iii) Given two chemical tests that could be used to distinguish between them. 28. (a) Write the formulas for the following compounds, using brackets to enclose the complex ion portion (i) Bromotriammineplatinum(II) nitrite (ii) Dichlorobis(ethylenediamine)cobalt(II) bromide (iii) Sulphatopentaamminecobalt(III) bromide (iv) Dibromotetraamminecobalt(III)tetrachlorozincate(II) (b) How do [PtCl2(NH3)2] and [Pt(NH3)6]Cl4 differ in their electrolytic conductance. What are hybridization states of Pt in these compounds? (c) Using well defined electronic configuration and (when necessary) hybridization pattern account for the following (i) The complex [ Fe(CN)6]-3 is an inner orbital complex whereas [ Fe(H2O)6]+3 is outer orbital complex ion (ii) Shape and magnetic properties of the complex [ Co(CO)4]+ (iii) Ni in its ground state appears to have unpaired electrons but the complex [Ni(CN)4]-2 is diamagnetic 29. (a) Using hybrization principles , prove that the complex (i) [Ni (CN)5]3- is dsp3 hybridized (ii) [Fe (CN)6]4- is d2sp3 (ii) [CoF6]3- is sp3d2 hybridized. (b) Balance the following redox reactions using half oxidation and reduction (i) SO - 2- 2 + MnO4 SO4 + Mn2+ (ii) H2O2 + H2C2O4 CO2 + H2O (c) What mass of KIO3 would be required to make 500cm3 of solution containing one sixtieth of a mole per litre? 30. Explain the following (a) Some of the compounds of Li have partially covalent character (b) Al is more metallic than Boron although both are found in group III of the periodic table. (c) BiCl5 and NCl5 cannot form while the other pentachlorides of group V exists. (d) Pbcl4 is covalent while PbCl2 is ionic and sparingly soluble. (e) AgCl is white ppt soluble in NH3(aq) (f) Silver nitrate is negligibly soluble in dilute hydrochloric acid but dissolves readily in concentrated hydrochloric acid. (g) Iron (III) compounds are stable than Iron (II) compounds. (h) When ammonium solution is added to into aqueous of Cu2+ ions, pale blue precipitate will appear ,but these will dissolve in excess of alkali to form a deep blue solution. (i) Silver nitrate may react with the compound [Pt(NH3)3Cl3]Cl but not with the compound [Pt(NH3)2Cl4]. 31. (a) ` State which oxidation state of manganese is most stable. Explain. (b) Explain why nickel (Ni) ;- (i) Is ferromagnetic. (ii) Conducts heat and electricity. (iii) Exhibit variable oxidation states. (iv) Is used as catalyst a catalyst in hydrogenation of unsaturated hydrocarbons. (c) Compounds containing the Zn2+ are colourless while those containing Cr3+ are coloured. Explain. [Co(CN)6]3- is yellow while [Co(NH3)6]3+ .Explain the colour differences in the compounds above.