Write the equilibrium constant expression for the overall reaction. Omitting the water molecules bound to Cu2+ for simplicity, we can write the equilibrium reactions as follows: The sum of the stepwise reactions is the overall equation for the formation of the complex ion: The hydrated Cu2+ ion contains six H2O ligands, but the complex ion that is produced contains only four $$NH_3$$ ligands, not six. (8) This is NOT an exhaustive list of shapes, but these are the ones you are most likely to encounter in an introductory inorganic chemistry course. Substituting these quantities into the equilibrium constant expression for the net reaction and assuming that x << 1.0, That is, AgCl dissolves in 1.0 M KCl to produce a 1.9 × 10−5 M solution of the AgCl2− complex ion. AP Chem students need to be able to write balanced net ionic equations for the formation of complex ions. Well-formed, stable negative images appear in tones of gray, corresponding to the number of grains of AgBr converted, with the areas exposed to the most light being darkest. The Roman numeral III indicates the oxidation state of Ruthenium. Subscribe to RSS headline updates from: Powered by FeedBurner. (7) If more than one type of ligand is present, the symbols are given in alphabetical order, eg, if Cl- and NH3 both occur as ligands in the same coordination compound, then, because C occurs before N in the alphabet, so we write [CrCl2(NH3)4]+ The formula of the complex is written [Co (H 2 O) 6] 3+ The hexaamminenickel (II) ion at the right has six ammonia molecules surrounding the central nickel 2+ ion in an octahedral arrangement. Write the formula and the name of each complex ion. Hence, the formula of pentaammineaquaruthenium (III) ion is [ Ru (NH 3) 5 H 2 O] 3 +. A complex is a substance in which a metal atom or ion is associated with a group of neutral molecules or anions called ligands.Coordination compounds are neutral substances (i.e. $Cu^{2+}_{(aq)} + 4NH_{3(aq)} \rightleftharpoons [Cu(NH_3)_4]^{2+}_{(aq)} \label{17.3.2}$. A negatively charged complex ion is called an anionic complex. The formation of a complex ion is a stepwise process and … No ads = no money for us = no free stuff for you! The shape, or geometry, of a number of complex ions is given in the table below: Footnotes: reference "Nomenclature of Inorganic Chemistry: IUPAC Recommendations 2005" (Red Book). Examples of complex ions are [Fe(H 2 O) 6] 2+, [CoCl 4] 2-, [Cu(NH 3) 4 (H 2 O) 2] 2+, [V(H 2 O) 6] 3+. Solve for the concentration of the complex ion. Because Gd3+(aq) is quite toxic, it must be administered as a very stable complex that does not dissociate in the body and can be excreted intact by the kidneys. Adding an ionic compound that contains Cu2+ to an aqueous ammonia solution will result in the formation of [Cu(NH3)4]2+(aq), as shown in Equation $$\ref{17.3.2}$$. (In fact, the measured solubility of AgCl in 1.0 M KCl is almost a factor of 10 greater than that in pure water, largely due to the formation of other chloride-containing complexes.). Note the change: previously we wrote the symbols for anionic ligands before the symbols for neutral ligands. X in the formula is equal the number of H 2 O ligands displaced by NH 3 ligands. Write the formula: The solution could also be called tetraquacopper (II) sulfate because there is a sulfate ion present. [Al(H 2 O) 6] 3+ is usually just called the hexaaquaaluminium ion rather than the hexaaquaaluminium(III) ion. Because the properties of water do not depend very much on whether it is inside a cell or in the blood, it is hard to get detailed images of these tissues that have good contrast. Further additions of metal ion give solutions that contain insufficient salicylic acid to complex with all the metal, so absorbance due to the complex … Thus the solubility of AgCl in pure water at 25°C is 1.33 × 10−5 M. If the common ion effect were the only important factor, we would predict that AgCl is approximately five orders of magnitude less soluble in a 1.0 M KCl solution than in water. Learn how in this brief webcast! The 2+ ion is almost the same colour as the hexaaquacopper(II) ion, and the 3+ ion is the hard-to-describe violet-blue-grey colour. Recent developments in chemistry written in language suitable for students. For negatively charged complex ions. Complex Ion Equilibria Thus we predict that AgCl has approximately the same solubility in a 1.0 M KCl solution as it does in pure water, which is 105 times greater than that predicted based on the common ion effect. In this case, the expression is as follows: $K_\textrm f=\dfrac{\left[[\mathrm{Cu(NH_3)_4}]^{2+}\right]}{[\mathrm{Cu^{2+}}][\mathrm{NH_3}]^4}=2.1\times10^{13}=K_1K_2K_3K_4\label{17.3.3}$. Kf is called the formation constant. Missed the LibreFest? The LibreTexts libraries are Powered by MindTouch® and are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. The reaction for the dissolution of silver bromide is as follows: $AgBr_{(s)} \rightleftharpoons Ag^+_{(aq)} + Br^{−}_{(aq)} \label{17.3.4a}$, $K_{sp} = 5.35 \times 10^{−13} \text{ at 25°C} \label{17.3.4b}$. The equilibrium constant expression for Kf has the same general form as any other equilibrium constant expression. When a patient is injected with a paramagnetic metal cation in the form of a stable complex known as an MRI contrast agent, the magnetic properties of water in cells are altered. Examples: The copper ammine ion, Cu (NH 3) 62+ is a complex ion. One of the most important metal ions for this application is Gd3+, which with seven unpaired electrons is highly paramagnetic. # Objectives!! a. a complex ion with $\mathrm{Co}^{3+}$ as the central ion and three $\mathrm{NH}_{3}$ molecules and three CN- ions as ligands b. a complex ion with $\mathrm{Cr}^{3+}$ as the central ion and a coordination number of 6 with ethylenediamine ligands (4) This is true for the names of simple ligands. The central ion is the coordination center, while the molecules or ions bound to it are termed complexing agents or ligands. The key to using complex-ion equilibria to dissolve an insoluble salt is simple: Choose a complex for which K f is large enough that the concentration of the uncomplexed metal ion is too small for the ion product to … The aim of this investigation is to determine the formula of the complex ion formed from copper (II) ions and ammonia through colorimetry. The formation constants for some common complex ions are listed in Table $$\PageIndex{1}$$. To# explore# complex# ions# and# coordination numbers.# To#use#absorptionspectroscopy#and#Job’s#method# to#determine#the#formula#of#a#complex#ion.# # Introduction! Formation of the [Cu(NH3)4(H2O)2]2+ complex is accompanied by a dramatic color change, as shown in Figure $$\PageIndex{1}$$. Experiment!23:!Determinationof!theFormula!of!a!Complex!Ion! The equilibrium constant for the formation of the complex ion is the formation constant (Kf). Consequently, many states in the United States have banned the use of phosphate-containing detergents, and France has banned their use beginning in 2007. This form of additive nomenclature has been in use for a very long time, but it has problems, notably it may not accurately reflect the distribution of electrons within the complex ion. Curriculum Notes . Small, highly charged metal ions, such as Cu2+ or Ru3+, have the greatest tendency to act as Lewis acids, and consequently, they have the greatest tendency to form complex ions. (1) Historically, coordination compounds were considered to be formed by adding independently stable compounds to a simple central atom or ion. then the shape of the complex ion is linear, If coordination number (= number of ligands) = 4 Differing from zinc and mercury, cadmium can form the complex… We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. Complex Formula with Wildcard Characters. A complex ion forms from a metal ion and a ligand because of a Lewis acid–base interaction. Technique:AbsorbanceSpectroscopy! The positively charged metal ion acts as a Lewis acid, and the ligand, with one or more lone pairs of electrons, acts as a Lewis base. The development of phosphate substitutes is an area of intense research. For example, if the lookup value is “VIVO” and in the main table if it is “VIVO Mobile” we can still match using wildcard characters. Writing formula of complex ions To write the formula of a complex ion you must remember to: • Place the whole formula in square brackets [ ] • Place the charge on the outside of the square brackets [Ag(NH 3) 2]+ Working out the charge of complex ions OH‐has a charge of ‐1NH 3 has a charge of 0 A complex ion is a species formed between a central metal ion and one or more surrounding ligands, molecules or ions that contain at least one lone pair of electrons. The equilibrium concentration of Cu2+(aq) in a 1.00 M ammonia solution is therefore 2.1 × 10−14 M. The ferrocyanide ion {[Fe(CN)6]4−} is very stable, with a Kf of 1 × 1035. A coordination complex consists of a central atom or ion, which is usually metallic and is called the coordination centre, and a surrounding array of bound molecules or ions, that are in turn known as ligands or complexing agents. A The initial concentration of Cu2+ from the amount of added copper nitrate prior to any reaction is as follows: Because the stoichiometry of the reaction is four NH3 to one Cu2+, the amount of NH3 required to react completely with the Cu2+ is 4(0.0846) = 0.338 M. The concentration of ammonia after complete reaction is 1.00 M − 0.338 M = 0.66 M. These results are summarized in the first two lines of the following table. Concept!Under!Investigation:!Complex!Ions! Central Ion Name Complex Ion Name [Ag(NH 3)] 2 + ammine : 2 → di: silver(I) +1= x + 2(0) x = +1: diamminesilver(I) ion (complex is a cation) THEORY The Ni 2+ cation forms a complex ion with H 2 O ligands in aqueous solutions. Coordination compounds are neutral substances (i.e. This is the traditional slogan but we can still fetch the data by using particle lookup value. Send Gift Now Le Chatelier’s principle tells us, however, that we can drive the reaction to the right by removing one of the products, which will cause more AgBr to dissolve. Empirical formula determination is difficult with a mixture of the two complex ions. Identify the oxidation state of the central metal ion (shown in parantheses): Calculate the total charge on the ligands: Write the formula giving the central metal ion first followed by the ligands, everything enclosed in square brackets followed by the charge on the ion as a superscript: If coordination number (= number of ligands) = 2 The numbers of ligands in a complex are specified using a Greek prefix: Oxidation state of the central metal atom is shown with a Roman numeral in parantheses at the end of the metal's name: The complex ion is an anion, therefore the name will end in ferrate(III), Ligands are named before central metal ion: hexacyanidoferrate(III). They are a type of coordination complex. As an example of the formation of complex ions, consider the addition of ammonia to an aqueous solution of the hydrated Cu2+ ion {[Cu(H2O)6]2+}. Also note that hydride becomes hydrido when coordinating to all elements EXCEPT boron. If desired, the silver can be recovered from the thiosulfate solution using any of several methods and recycled. The formula of complex ion formed when aluminum hydroxide dissolves in sodium hydroxide will be: Select the correct answer below: [AlOH]2+ [Al(OH)2]+ If the oxidation state is zero, then an arabic 0 is placed in parentheses. Anionic ligands have names ending in 'o'. “Phosphate-free” detergents contain different kinds of complexing agents, such as derivatives of acetic acid or other carboxylic acids. Six is the most common coordination number, although 4 and 2 are also known. The hydroxyaluminate or hydrated aluminate can be precipitated and then calcined to produce anhydrous aluminates. eg, [CoCl(NH3)5]Cl2 is pentaaminechloridocobalt(2+) chloride. If a complex ion has a large Kf, the formation of a complex ion can dramatically increase the solubility of sparingly soluble salts. To determine: The formula of the complex ion pentaammineaquaruthenium (III) ion. The replacement of water molecules from [Cu(H2O)6]2+ by ammonia occurs in sequential steps. Pay for 5 months, gift an ENTIRE YEAR to someone special! So the equilibrium lies to the right, and this a stable complex ion. Note the change of name when water is a ligand from the previous "aquo" to the new "aqua". Legal. ? A hydrated ion is one kind of a complex ion (or, simply, complex), a species formed between a central metal ion and one or more surrounding ligands, molecules or ions that contain at least one lone pair of electrons, such as the [Al(H2O)6]3+ ion. Naming Coordination Compounds. The value of x indicates that our assumption was justified. For a more complete description, see https://www.youtube.com/watch?v=IQNcLH6OZK0. As a result, removing unreacted AgBr from even a single roll of film using pure water would require tens of thousands of liters of water and a great deal of time. There are other, arguably better, systematic IUPAC ways to name a complex ion, for example, you could name the complex ion as an ion (see Naming cations and Naming Anions) in which case you enclose the charge on the ion in round brackets after the additive name (no need to try to determine the oxidation state of the metal and hence removes the problem of electron distribution). Given: Ksp of AgCl, Kf of AgCl2−, and KCl concentration, Asked for: solubility of AgCl in water and in KCl solution with and without the formation of complex ions. VLOOKUP requires an exact lookup value to be matched to fetch the data. Observe the peacock blue solution of copper (II) sulfate. For complex ligand names, the prefixes bis, tris, tetrakis etc are used with enclosing marks around the multiplicand in order to aviod ambiguity. (3) The names of cationic ligands are also used without modification, even if the name ends in "ide", "ate" or "ite". In the given ion, metal ion Ruthenium (Ru 3 +) contains five Ammonia (NH 3) and one Water (aqua) ligand. Complexing agents, molecules or ions that increase the solubility of metal salts by forming soluble metal complexes, are common components of laundry detergents. Their order in the formula is the opposite of that in the complex's name since one uses their chemical symbols and the other uses the names of the ligands. MRI is based on the magnetic properties of the 1H nucleus of hydrogen atoms in water, which is a major component of soft tissues. Because the equilibrium constant for the reaction is large (2.1 × 1013), the equilibrium will lie far to the right. You will learn more about coordination compounds in the lab lectures of experiment 4 in this course. Each blog post includes links to relevant AUS-e-TUTE tutorials and problems to solve. Have questions or comments? Due to the common ion effect, we might expect a salt such as AgCl to be much less soluble in a concentrated solution of KCl than in water. then the shape of the complex ion is tetrahedral or square-planar, If coordination number (= number of ligands) = 6 then the shape of the complex ion is octahedral. Calculate the concentration of cyanide ion in equilibrium with a 0.65 M solution of K4[Fe(CN)6]. (6) If more than one type of ligand is present, the ligands are named in alphabetical order (disregard any multiplicative prefixes when determining that order), ⚛ iron(II) → ferrate(II) The formation of a complex ion by adding a complexing agent increases the solubility of a compound. And notice the equilibrium constant for this. We can see the effect of thiosulfate on the solubility of AgBr by writing the appropriate reactions and adding them together: Comparing K with Ksp shows that the formation of the complex ion increases the solubility of AgBr by approximately 3 × 1013. Splitting is greater if the ion is octahedral than if it is tetrahedral, and therefore the colour will change with a change of co-ordination. Identify the oxidation state on the central metal ion (shown in Roman numerals parantheses), Calculate the total charge on the ligands. Thus we will assume that the formation of [Cu(NH3)4]2+ in the first step is complete and allow some of it to dissociate into Cu2+ and NH3 until equilibrium has been reached. uncharged) in which at least one ion is present as a complex. ⚛ tin(IV) → stannate(IV). When mixed with aqueous NH 3, some of the 6 H 2 O ligands are displaced with NH 3 ligands forming a complex ion Ni(H 2 O) 6-X (NH 3) X 2+. Small, highly charged metal ions have the greatest tendency to act as Lewis acids and form complex ions. (a) What is the formula of a complex ion composed of one Co 3+ ion, three ammonia molecules, and three Cl − ions? An aqueous solution of CuSO4 consists of hydrated Cu2+ ions in the form of pale blue [Cu(H2O)6]2+ (left). Figure $$\PageIndex{2}$$: An MRI Image of the Heart, Arteries, and Veins. Correct formula for the complex ion is [Ni(en) 3 ]2+ 16 Determining the Coordination Number of Ni 2+ and Cu by Enthalpy Sample Data Calculations for the [Ni(OH 26) ]2+ series: Trial 1 Q = [55 ml soln x 1.00 g soln x 0.80 °C x 4.18 J + 0.80 °C x 10 J] -1 When dissolved in bases it forms hydroxyaluminate ions in the same way as aluminium hydroxide or aluminium salts. Given: mass of Cu2+ salt and volume and concentration of ammonia solution, Asked for: equilibrium concentration of Cu2+(aq). ⚛ gold(I) → aurate(I) We assume that the volume change caused by adding solid copper(II) nitrate to aqueous ammonia is negligible. ⚛ silver(I) → argentate(I) Write the formula of a complex ion with four water molecules and two ONO- ions connected to an Fe (III) ion. Aluminate oxyanions. Its formula is Ni(H 2 O) 6 2+. Long-chain carboxylic acids, the major components of soaps, form insoluble salts with Ca2+ and Mg2+, which are present in high concentrations in “hard” water. The sulfate ion is not part of the complex ion. Watch the recordings here on Youtube! Please enable javascript and pop-ups to view all page content. The mixture becomes clear due to the formation of a complex ion that is soluble in water. The complexing agents used for gadolinium are ligands such as DTPA5− (diethylene triamine pentaacetic acid), whose fully protonated form is shown here. 1.6 times 10 to the seventh. To be introduced to complex ions, including ligands. Complex ions that form with the Fe3+ have a different number of oxalate groups than those that form with Fe2+. (2) Previously, anionic ligands were named by removal of "ide" and replacement by "o", for example chloride became chloro, and, removal of "ate" and replacement with "o" for example sulfate became sulfo. Commercial water softeners also use a complexing agent to treat hard water by passing the water over ion-exchange resins, which are complex sodium salts. Write the formula giving the central metal ion first followed by the ligands, and enclose everything except the charge in square brackets: The coordination number of the complex ion is the number of bonds formed between the central metal ion and its ligands. With Kf = 2.1 × 1013, the [Cu(NH3)4(H2O)2]2+ complex ion is very stable. A complex ion forms from a metal ion and a ligand because of a Lewis acid–base interaction. A complex ion is a polyatomic species consisting of a central metal ion surrounded by several ligands. Such an assumption would be incorrect, however, because it ignores the fact that silver ion tends to form a two-coordinate complex with chloride ions (AgCl2−). As for any equilibrium, the larger the value of the equilibrium constant (in this case, Kf), the more stable the product. The equilibrium lies far to the left, and the equilibrium concentrations of Ag+ and Br− ions are very low (7.31 × 10−7 M). A coordination complex is a substance in which a metal atom or ion accepts electrons from (and thus associates with) a group of neutral molecules or anions called ligands.A complex can be an anion, a cation ion, or a neutral molecule. When water flows over the resin, sodium ion is dissolved, and insoluble salts precipitate onto the resin surface. Adding a complexing agent such as pyrophosphate (O3POPO34−, or P2O74−) or triphosphate (P3O105−) to detergents prevents the magnesium and calcium salts from precipitating because the equilibrium constant for complex-ion formation is large: However, phosphates can cause environmental damage by promoting eutrophication, the growth of excessive amounts of algae in a body of water, which can eventually lead to large decreases in levels of dissolved oxygen that kill fish and other aquatic organisms. The magnitude of the equilibrium constant indicates that almost all Ag+ ions in solution will be immediately complexed by thiosulfate to form [Ag(S2O3)2]3−. The nickel ion has an oxidation state of 2+ and each of the ammonia molecules is neutral, so the overall charge on the complex ion is: 2+ + 0 = 2+ ]^2+ ion the four ammine ligands are named first. To solve this problem, scientists have developed a class of metal complexes known as “MRI contrast agents.” Injecting an MRI contrast agent into a patient selectively affects the magnetic properties of water in cells of normal tissues, in tumors, or in blood vessels and allows doctors to “see” each of these separately (Figure $$\PageIndex{2}$$). When the shutter of the camera opens, the light from the object being photographed strikes some of the crystals on the film and initiates a photochemical reaction that converts AgBr to black Ag metal. ⚛ copper(I) → cuprate(I) Calculate the solubility of AgCl in each situation: At 25°C, Ksp = 1.77 × 10−10 for AgCl and Kf = 1.1 × 105 for AgCl2−. The table below lists some common polar molecules which can be present as ligands: The table below lists some anions which can be present as ligands: Example: Name the complex ion with the forumla [Fe(CN)6]3-, Example: write the formula for the complex ion tetraamminecopper(II). A hydrated ion is one kind of a complex ion (or, simply, complex), a species formed between a central metal ion and one or more surrounding ligands, molecules or ions that contain at least one lone pair of electrons, such as the [Al(H 2 O) 6] 3+ ion. D If we let x equal the solubility of AgCl in the KCl solution, then at equilibrium [AgCl2−] = x and [Cl−] = 1.0 − x. Naming of these coordination compounds was therefore based on an additive principle whereby the names of added compounds and the central atom were combined. To fix the image and prevent more AgBr crystals from being converted to Ag metal during processing of the film, the unreacted AgBr on the film is removed using a complexation reaction to dissolve the sparingly soluble salt. Hence, the name of the complex ion is tetra ammine copper (2) 3) A complex anion named by writting ligands followed by name of the metal ending with suffix- ate. Aluminium oxide (alumina) is amphoteric: it dissolves in both bases and acids. It is followed by copper metal along with its oxidation state. Note the changes: final "e" is removed and replaced by "o", chloride becomes chlorido and sulfate becomes sulfato. Water, a pure liquid, does not appear explicitly in the equilibrium constant expression, and the hydrated Cu2+(aq) ion is represented as Cu2+ for simplicity. One such example occurs in conventional black-and-white photography. Amminetetraaquachromium(II) ion would be written as [Cr(H 2 O) 4 (NH 3)] +2. uncharged) in which at least one ion is present as a complex. Unlike x-rays, magnetic resonance imaging (MRI) can give relatively good images of soft tissues such as internal organs. Because it is a stronger base than H2O, ammonia replaces the water molecules in the hydrated ion to form the [Cu(NH3)4(H2O)2]2+ion. For more information contact us at info@libretexts.org or check out our status page at https://status.libretexts.org. The equilibrium constant for the formation of the complex ion from the hydrated ion is called the formation constant (Kf). I. In this tutorial we will name the complex ion using the oxidation state for the central metal atom. (1999). Bromide ion is difficult to remove chemically, but silver ion forms a variety of stable two-coordinate complexes with neutral ligands, such as ammonia, or with anionic ligands, such as cyanide or thiosulfate (S2O32−). As an example of the formation of complex ions, consider the addition of ammonia to an aqueous solution of the hydrated Cu2+ion {[Cu(H2O)6]2+}. Most transition metal cations can do something interesting in solution, they can interact with specific ligands to form complex ions. Using Complex Ion Equilibria to Dissolve an Insoluble Salt . Ligands are named before the central metal atom. The final concentrations of all species (in the bottom row of the table) are the sums of the concentrations after complete reaction and the changes in concentrations. Some content on this page could not be displayed. Write the formula and name of (a) a complex ion having \mathrm{Cr}^{3+} as the central ion and two \mathrm{NH}_{3} molecules and four \mathrm{Cl}^{-} ions as l… Give the gift of Numerade. If we define x as the amount of Cu2+ produced by the dissociation reaction, then the stoichiometry of the reaction tells us that the change in the concentration of [Cu(NH3)4]2+ is −x, and the change in the concentration of ammonia is +4x, as indicated in the table. Recall that black-and-white photographic film contains light-sensitive microcrystals of AgBr, or mixtures of AgBr and other silver halides. Please do not block ads on this website. Neutral ligands are named as the molecule without modification, with these notable exceptions: The numbers of ligands in a complex are specified using the Greek prefixes: The name of a cationic complex ion ends in the name of the central metal ion with the, The name of an anionic complex ion ends in '. The reaction of Ag+ with thiosulfate is as follows: $Ag^+_{(aq)} + 2S_2O^{2−}_{3(aq)} \rightleftharpoons [Ag(S_2O_3)_2]^{3−}_{(aq)} \label{17.3.5a}$, $K_f = 2.9 \times 10^{13} \label{17.3.5b}$. The solution changes from the light blue of [Cu(H2O)6]2+ to the blue-violet characteristic of the [Cu(NH3)4(H2O)2]2+ ion. (adsbygoogle = window.adsbygoogle || []).push({}); Want chemistry games, drills, tests and more? If 12.5 g of Cu(NO3)2•6H2O is added to 500 mL of 1.00 M aqueous ammonia, what is the equilibrium concentration of Cu2+(aq)? The dramatic increase in solubility combined with the low cost and the low toxicity explains why sodium thiosulfate is almost universally used for developing black-and-white film. Many metal-containing compounds, especially those of transition metals, are coordination complexes. [ "article:topic", "showtoc:no", "license:ccbyncsa", "program:hidden" ], https://chem.libretexts.org/@app/auth/2/login?returnto=https%3A%2F%2Fchem.libretexts.org%2FBookshelves%2FGeneral_Chemistry%2FBook%253A_Chemistry_(Averill_and_Eldredge)%2F17%253A_Solubility_and_Complexation_Equilibria%2F17.3%253A_The_Formation_of_Complex_Ions, \begin{align}\mathrm{Cu^{2+}(aq)}+\mathrm{NH_{3(aq)}}&\rightleftharpoons\mathrm{[Cu(NH_3)]^{2+}_{(aq)}}\hspace{5mm}K_1, \[12.5\mathrm{\;\cancel{g}\;Cu(NO_3)_2}\cdot\mathrm{6H_2O}\left(\dfrac{\textrm{1 mol}}{\textrm{295.65} \cancel{g}} \right )\left(\dfrac{1}{\textrm{500}\; \cancel{mL}} \right )\left(\dfrac{\textrm{1000}\; \cancel{mL}}{\textrm{1 L}} \right )=\textrm{0.0846 M}, \begin{align}K_\textrm f&=\dfrac{\left[[\mathrm{Cu(NH_3)_4}]^{2+}\right]}{[\mathrm{Cu^{2+}}][\mathrm{NH_3}]^4}=\dfrac{0.0846-x}{x(0.66+4x)^4}\approx\dfrac{0.0846}{x(0.66)^4}=2.1\times10^{13}, \begin{align}\mathrm{AgBr(s)}\rightleftharpoons\mathrm{Ag^+(aq)}+\mathrm{Br^-(aq)}\hspace{3mm}K_{\textrm{sp}}&=5.35\times10^{-13}, \(\begin{align}\mathrm{AgCl(s)}\rightleftharpoons\mathrm{Ag^+(aq)}+\mathrm{Cl^-(aq)}\hspace{3mm}K_{\textrm{sp}}&=1.77\times10^{-10}, \(K=\dfrac{[\mathrm{AgCl_2^-}]}{[\mathrm{Cl^-}]}=\dfrac{x}{1.0-x}\approx1.9\times10^{-5}=x, \[Ca^{2+}_{(aq)} + O_3POPO^{4−}_{4(aq)} \rightleftharpoons [Ca(O_3POPO_3)]^{2−}_{(aq)} \label{17.3.7a}, 17.0: Prelude to Solubility and Complexation Equilibria, The Effect of the Formation of Complex Ions on Solubility, https://www.youtube.com/watch?v=IQNcLH6OZK0, information contact us at info@libretexts.org, status page at https://status.libretexts.org. 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