11.3. Some reactions of the halide ions
A subsection of Chemistry, 9701, through 11. Group 17
Listing 10 of 171 questions
Define transition element. Explain why transition elements can form complex ions. The 3d orbitals in an isolated Ag+ ion are degenerate. Define degenerate d orbitals. Sketch the shape of a 3dxy orbital in . z y x Tollens’ reagent can be used to distinguish between aldehydes and ketones. Tollens’ reagent contains [Ag(NH3)2]OH, which can be prepared in a two-step process. step 1 Aqueous NaOH is added dropwise to aqueous AgNO3 to form Ag2O as a brown precipitate. step 2 Aqueous NH3 is added dropwise to Ag2O to form a colourless solution containing [Ag(NH3)2]OH. Construct equations for each of the steps in the preparation of [Ag(NH3)2]OH. step 1 step 2 Name the shape of the complex ion [Ag(NH3)2]+. State the bond angle for H-N-Ag and for N-Ag-N. shape bond angle for H-N-Ag = ° bond angle for N-Ag-N = ° An electrochemical cell uses Ag2O as the positive electrode and Zn as the negative electrode immersed in an alkaline electrolyte. The overall cell reaction is shown. Ag2O + Zn + H2O 2Ag + Zn(OH)2 Complete the half-equation for the reaction at each electrode. at the positive electrode Ag2O + at the negative electrode Zn + Coordination polymers are made when a bidentate ligand acts as a bridge between different metal ions. Under certain conditions Ru3+and the bidentate ligand dps can form a coordination polymer containing ([RuCl 4]–)n chains. N N S dps The bidentate ligand dps uses each of the nitrogen atoms to bond to a different Ru3+. Complete by drawing the structure for the coordination polymer ([RuCl 4]–)n. Show two repeat units. The dps ligand can be represented using N N . Ru
9701_s24_qp_43
THEORY
2024
Paper 4, Variant 3
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Describe and explain how the basicities of ammonia, ethylamine and phenylamine differ. CH3CH2NH2 NH3 NH2 ammonia ethylamine phenylamine Describe how the use of aqueous silver nitrate and aqueous ammonia can distinguish between aqueous solutions containing chloride, bromide or iodide ions by filling in the following table. halide observation when AgNO3is added observation when dilute NH3is added observation when concentrated NH3is added chloride bromide iodide Silver bromide is sparingly soluble in water. AgBrAg++ Br–Ksp = 5 × 10–13 mol2 dm–6 Calculate [Ag+] in a saturated aqueous solution of AgBr. [Ag+] = mol dm–3 State and explain whether AgBr will be less or more soluble in 0.1 mol dm–3 KBr than it is in pure water. Silver ions form complexes with ammonia and with amines. Ag++ 2RNH2[Ag(RNH2)2]+Write an expression for the Kc for this reaction, and state its units. Kc = units Kc has the numerical value of 1.7 × 107 when R = H. Using your expression for Kc calculate the needed to change the [Ag+] in a 0.10 mol dm–3 solution of silver nitrate to the value that you calculated in . = mol dm–3 Explain whether you would expect the Kc for the reaction where R = C2H5 to be greater or less than that for the reaction where R = H.
9701_w09_qp_42
THEORY
2009
Paper 4, Variant 2
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What is meant by the term ligand in the context of transition element chemistry? Decide which of the following species could be a ligand, and which could not be. Place a tick (✓) in the appropriate column. species can be a ligand cannot be a ligand OH– NH4 + CH3OH CH3NH2 Read the following description of some reactions of copper(sulfate, and answer the questions that follow. When 0.1 mol of white anhydrous CuSO4 is dissolved in liquid ammonia at –33 °C, a deep blue solution C results. When 0.2 mol of solid NaOH is added to solution C, and the ammonia solvent allowed to evaporate, a solid residue is obtained. Heating this residue to 200 °C produces a dark coloured mixture of two solids. When water is added to this mixture, a black solid D and a colourless solution E are formed. Neither D nor E contains nitrogen. Adding BaCl2to solution E produces a white precipitate F. Solid D dissolves in HNO3on warming, without evolution of gas, to give a pale blue solution containing Cu(NO3)2. Suggest the formula of the compound contained in each of the following. solution C solid D solution E white precipitate F Name the type of reaction that is occurring when D reacts with HNO3. Describe what you would observe when a solid sample of anhydrous Cu(NO3)2 is strongly heated. Write an equation for this reaction.
9701_w10_qp_41
THEORY
2010
Paper 4, Variant 1
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What is meant by the term ligand in the context of transition element chemistry? Decide which of the following species could be a ligand, and which could not be. Place a tick (✓) in the appropriate column. species can be a ligand cannot be a ligand OH– NH4 + CH3OH CH3NH2 Read the following description of some reactions of copper(sulfate, and answer the questions that follow. When 0.1 mol of white anhydrous CuSO4 is dissolved in liquid ammonia at –33 °C, a deep blue solution C results. When 0.2 mol of solid NaOH is added to solution C, and the ammonia solvent allowed to evaporate, a solid residue is obtained. Heating this residue to 200 °C produces a dark coloured mixture of two solids. When water is added to this mixture, a black solid D and a colourless solution E are formed. Neither D nor E contains nitrogen. Adding BaCl2to solution E produces a white precipitate F. Solid D dissolves in HNO3on warming, without evolution of gas, to give a pale blue solution containing Cu(NO3)2. Suggest the formula of the compound contained in each of the following. solution C solid D solution E white precipitate F Name the type of reaction that is occurring when D reacts with HNO3. Describe what you would observe when a solid sample of anhydrous Cu(NO3)2 is strongly heated. Write an equation for this reaction.
9701_w10_qp_42
THEORY
2010
Paper 4, Variant 2
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