11.3. Some reactions of the halide ions
A subsection of Chemistry, 9701, through 11. Group 17
Listing 10 of 171 questions
In this question, K, L and M refer to a halogen atom or halide ion. For each part question, read the information and complete the answer lines below. When concentrated sulfuric acid is added to solid NaK, white fumes are produced that turn damp blue litmus paper red. No other colour changes are observed. identity of K = equation for reaction explanation of observation When silver nitrate solution is added to an aqueous solution of NaL, a precipitate forms that remains after the addition of concentrated ammonia solution. identity of L = colour of precipitate equation for reaction M2 is a liquid at room temperature with a boiling point higher than that of chlorine but lower than that of iodine. identity of M = explanation The diagram below is a simplifi ed representation of a diaphragm cell. + – titanium anode diaphragm steel cathode concentrated brine product D product B product C Identify each of the products. B C D Give the equations for the two electrode reactions. anode cathode
9701_s14_qp_21
THEORY
2014
Paper 2, Variant 1
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Copper is a transition element with atomic number 29. Complete the electronic configurations of a Cu atom and a Cu+ ion. Cu atom 1s22s22p6 Cu+ ion 1s22s22p6 Cu+ ions form a linear complex with Cl – ions, which are monodentate ligands. Draw the structure of this complex and include its overall charge. Cu2+ ions exist as [Cu(H2O)6]2+ complex ions in aqueous solution. Complete a three-dimensional diagram to show the shape of this complex. Name its shape. Label and state the value of one bond angle. Cu name of shape  When NH3is added to Cu2+, dropwise at first and then in excess, two chemical reactions occur as shown. [Cu(H2O)6]2+ A dropwise NH3reaction 1 B excess NH3reaction 2 For each reaction, describe what you would see and write an equation. reaction 1 observation equation reaction 2 observation equation EDTA4– is a polydentate ligand. When a solution of EDTA4– is added to a solution containing [Cu(H2O)6]2+ a new complex is formed. The formula of this complex is 2–. Name the type of reaction occurring here. Write an expression for the stability constant, Kstab, of 2– in this reaction. The numerical value of the Kstab of 2– is 6.3×1019 at 298 K. State what this tells us about the 2– complex ion. Ethanedioate ions, C2O4 2–, can act as a bidentate ligand. Explain what is meant by the term bidentate ligand. When ethanedioate ions are added to a solution of zirconium ions, Zr 4+, a complex ion containing four C2O4 2– ions and one Zr 4+ ion is formed. All four ethanedioate ions act as bidentate ligands in this complex. Give the formula of this complex ion and explain why this complex is not octahedral.
9701_s18_qp_41
THEORY
2018
Paper 4, Variant 1
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Copper is a transition element with atomic number 29. Complete the electronic configurations of a Cu atom and a Cu+ ion. Cu atom 1s22s22p6 Cu+ ion 1s22s22p6 Cu+ ions form a linear complex with Cl – ions, which are monodentate ligands. Draw the structure of this complex and include its overall charge. Cu2+ ions exist as [Cu(H2O)6]2+ complex ions in aqueous solution. Complete a three-dimensional diagram to show the shape of this complex. Name its shape. Label and state the value of one bond angle. Cu name of shape  When NH3is added to Cu2+, dropwise at first and then in excess, two chemical reactions occur as shown. [Cu(H2O)6]2+ A dropwise NH3reaction 1 B excess NH3reaction 2 For each reaction, describe what you would see and write an equation. reaction 1 observation equation reaction 2 observation equation EDTA4– is a polydentate ligand. When a solution of EDTA4– is added to a solution containing [Cu(H2O)6]2+ a new complex is formed. The formula of this complex is 2–. Name the type of reaction occurring here. Write an expression for the stability constant, Kstab, of 2– in this reaction. The numerical value of the Kstab of 2– is 6.3×1019 at 298 K. State what this tells us about the 2– complex ion. Ethanedioate ions, C2O4 2–, can act as a bidentate ligand. Explain what is meant by the term bidentate ligand. When ethanedioate ions are added to a solution of zirconium ions, Zr 4+, a complex ion containing four C2O4 2– ions and one Zr 4+ ion is formed. All four ethanedioate ions act as bidentate ligands in this complex. Give the formula of this complex ion and explain why this complex is not octahedral.
9701_s18_qp_43
THEORY
2018
Paper 4, Variant 3
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Aqueous solutions of copper(salts contain the blue-coloured [Cu(H2O)6]2+ complex ion. Separate portions of this blue solution react with aqueous sodium hydroxide and with concentrated hydrochloricacid. Give the following information for each of these reactions. ● ● reaction with aqueous sodiumhydroxide ionic equation type of reaction colour and state of the copper-containing product ● ● reaction with concentrated hydrochloricacid ionic equation type of reaction colour and state of the copper-containing product  Chloride ions can be identified using aqueous silvernitrate, AgNO3. Ag++ Cl –AgCl 0.303 g of a chloride of sulfur is completely hydrolysed with water. All the chlorine atoms present in the chloride of sulfur are converted into chloride ions. The solution is diluted to 100.0 cm3. A 25.00 cm3 sample of this solution is titrated with 0.0500 mol dm–3 AgNO3. The titration requires 22.40 cm3 of 0.0500 mol dm–3 AgNO3. Calculate the empirical formula of the chloride of sulfur. Show all your working.  empirical formula of chloride of sulfur = 
9701_s19_qp_41
THEORY
2019
Paper 4, Variant 1
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