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2023 Physics Forums, All Rights Reserved, Calculate the bond-dissociation energies and entropy of a molecule. Let's go through this example step-by-step! You are using an out of date browser. ThoughtCo. equation. Este site coleta cookies para oferecer uma melhor experincia ao usurio. In other words, if the acid is weak the concentration of the water is virtually constant. First, let's write out the base ionization reaction for ammonia. The free energy change at equilibrium is zero since the chemical potentials of reactants and products are equal at equilibrium. When one reactant forms two products in parallel, the macroconstant is a sum of two microconstants, We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. Calculate the value of the acid expression. The acid dissociation constant can be calculated by dividing the concentration of the products by the concentration of the reactants. In this experiment, students test ethanoic acid with universal indicator solution, magnesium, sodium hydroxide solution and sodium carbonate solution. K The discussion of weak and strong acids is probably more suited to advanced rather than intermediate students. writing the concentration of ethanoic acid in the denominator. Buffer solutions are used extensively to provide solutions at or near the physiological pH for the study of biochemical reactions;[67] the design of these solutions depends on a knowledge of the pKa values of their components. formic acid (HCO2H), also called methanoic acid, the simplest of the carboxylic acids, used in processing textiles and leather. Calculate the acid dissociation constant at this temperature Given that the ionic product of water is 1.0 times 10^-14 mol2dm-6 at 298K, calculate to 3 significant figures the pH at this temperature of a 0.0500M solution of sodium hydroxide. the reactants. Ethanoic acid is a weak acid that dissociates according to the following: CHCOOH H + CHCOO, What is the acid dissociation constant for this acid? An example, using ammonia as the base, is H 2 O + NH 3 OH + NH 4+. Therefore, the buffer regions will be centered at about pH1.3 and pH4.3. H+ aqueous equals 1.5 times 10 to the negative third moles per liter. , Extension of the Hammett scale through data for the ionization of substituted benzoic acids in aqueous solvents at 25C (Technical Report)", "Guidelines for NMR easurements for Determination of High and Low pK, AcidityBasicity Data in Nonaqueous Solvents, SPARC Physical/Chemical property calculator, List of predicted structure based properties, https://en.wikipedia.org/w/index.php?title=Acid_dissociation_constant&oldid=1149779154, The association constant for the formation of a, For polyprotic acids, the numbering of stepwise association constants is the reverse of the numbering of the dissociation constants. Direct link to Jayom Raval's post In the ICE tables, is the. [63] Software to perform the calculations is supplied by the instrument manufacturers for simple systems. 1.8.7 demonstrate knowledge and understanding that weak acids and weak alkalis are partially ionised in water, recall examples of weak acids (including ethanoic acid and carbonic acid) and recall examples of weak alkalis (including ammonia). p Use evidence-based research and teaching tips to solidify understandingof reaction mechanisms, Use these exam-style questions to check your learners understanding of experimental skills and strategies, Practical experiment where learners produce gold coins by electroplating a copper coin with zinc, includes follow-up worksheet. [66] Protein pKa values cannot always be measured directly, but may be calculated using theoretical methods. There are tables of acid dissociation constants, for easy reference. Add the copper carbonate to each tube in very small quantities, stirring with a glass rod, until nothing further happens. Direct link to p4q4storm's post for the example 1: calcul, Posted 6 years ago. HCOOH( )aq H 2 2()g CO g (e) Is the reaction a redox reaction? Methanoic Acid's dissociation constant | Physics Forums In acidbase extraction, the efficiency of extraction of a compound into an organic phase, such as an ether, can be optimised by adjusting the pH of the aqueous phase using an appropriate buffer. 3. ?. , Write the IUPAC name for the following: 2. place and in scientific notation. 1 The solution is then titrated with a strong base until all the protons have been removed. If this is the first set of questions you have done, please read the introductory page before you start. For example: ethanol + ethanoic acid ethyl ethanoate + water. dissociation constant for methanoic acid, HCOOH, using the following two Hydrochloric acid is a strong acid - virtually 100% ionised. Students should be able to: describe what happens when any of the first four carboxylic acids react with carbonates, dissolve in water, react with alcohols. OH- is actually considered to be a strong base, as its conjugate acid, water (H2O), is a weak acid. / decimal place, we have determined that the acid dissociation constant for methanoic or something? Second, some reactions are exothermic and some are endothermic, but, when H is negative TS is the dominant factor, which determines that G is positive. First, let's write the balanced dissociation reaction of, Plugging the equilibrium concentrations into our. Again, for simplicity, H3O + can be written as H + in Equation ?? You guys said the concentration I should have found is 0.0126M. 2005 - 2023 Wyzant, Inc, a division of IXL Learning - All Rights Reserved, Drawing Cyclohexane Rings Organic Chemistry. 4. Yours might want you to do it in a different order. A set of differentiated worksheets with answers to identify learning gaps and misconceptions on the topic of acids and bases. If you're seeing this message, it means we're having trouble loading external resources on our website. Nagwa is an educational technology startup aiming to help teachers teach and students learn. It may not display this or other websites correctly. This is sometimes called an ICE table: Plug in this value for x to solve for Ka: By clicking Accept All Cookies, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. They are listed in order of decreasing acid strength - the Ka values get smaller as you go down the table. . The data were critically selected and refer to 25C and zero ionic strength, in water.[11]. Dissociation of bases in water In this case, the water molecule acts as an acid and adds a proton to the base. + Between the two buffer regions there is an end-point, or equivalence point, at about pH3. If not, under what conditions would be higher (e.g. As a part of this it defines and explains what is meant by pH, Ka and pKa. Another example occurs in chemical oceanography:[83] in order to quantify the solubility of iron(III) in seawater at various salinities, the pKa values for the formation of the iron(III) hydrolysis products Fe(OH)2+, Fe(OH)+2 and Fe(OH)3 were determined, along with the solubility product of iron hydroxide.[84]. Students could be asked to write equations for the reactions that occur. . 16.4: Acid Strength and the Acid Dissociation Constant (Ka) You can get a measure of the position of an equilibrium by writing an equilibrium constant for the reaction. ) Use a dropping pipette to add one drop of sodium carbonate solution to the ethanoic acid tube which contains the indicator. Recall that acids react with some metals and with carbonates, and write equations predicting products from given reactants. Hydrochloric acid solution, HCl(aq) see CLEAPSSHazcardHC047aand CLEAPSSRecipe Book RB043. 1. Comparing fresh and seawater, the differences in the first and second dissociation constants of carbonic acid -K1 and K2 for freshwater, and K1' and K2' for seawater- and the consequences thereoff will appear spectacular. They cannot be determined directly by means of pH, absorbance, fluorescence or NMR measurements; a measured Kb value is the sum of the K values for the micro-reactions. . The products of the reaction, fluoride anion and the hydronium ion, are oppositely charged ions, and it is reasonable to assume that they will be attracted to each other. When alkalis are added, however, the ethanoic acid equilibrium position moves to the right, so eventually all the acid reacts, as shown in the equations below: NaOH + HCl NaCl + H2ONaOH + CH3COOH CH3COONa + H2O, Na2CO3 + 2HCl 2NaCl + CO2 + H2ONa2CO3 + 2CH3COOH 2CH3COONa + CO2 + H2O, Mg + 2HCl MgCl2 + H2Mg + 2CH3COOH (CH3COO)2Mg + H2, CuCO3 + 2HCl CuCl2 + CO2 + H2OCuCO3 + 2CH3COOH (CH3COO)2 Cu + CO2 + H2O. A weak acid is an acid which dissociates partially in aqueous solution. By contrast. the dissociation of ethanoic acid to write an acid dissociation constant At the bottom of the expression, you have a term for the concentration of the water in the solution. https://en.wikipedia.org/wiki/Acid_dissociation_constant#Acidity_in_nonaqueous_solutions, The base dissociation constant (or base ionization constant). Repeat step 10using the third ethanoic acid tube. The hydrochloric acid will fizz strongly with the sodium carbonate solution, whereas for ethanoic acid the fizzing will be detectable but less vigorous. For example: Calculate the acid dissociation constant Ka for a 0.2 M aqueous solution of propionic acid (CH3CH2CO2H) that is found to have a pH value of 4.88. a However, the pH does not continue to rise indefinitely. strong and weak acids - chemguide The second end-point begins at about pH6.3 and is sharp. 2.5.25 investigate experimentally the reactions of carboxylic acids with carbonates, hydroxides and metals, test any gases produced and write balanced symbol equations for these reactions. This website collects cookies to deliver a better user experience. The buffer capacity[75] of a simple buffer solution is largest when pH=pKa. It is important that you don't confuse the words strong and weak with the terms concentrated and dilute. Choose an expert and meet online. Nagwa uses cookies to ensure you get the best experience on our website. based on a series of buffer solutions. Find out! Similarly, a base such as spermine has more than one site where protonation can occur. Solutions of carboxylic acids have a pH less than 7 and like other acids, can react with metals, metal oxides, hydroxides and carbonates forming salts. Y An acid dissociation constant is Is there a situation like that? }, When a reactant undergoes two reactions in series, the macroconstant for the combined reaction is the product of the microconstant for the two steps. The Kb values for dissociation of spermine protonated at one or other of the sites are examples of micro-constants. As you rightly say, you can't have a negative concentration, so the viable answer is 0.01245 M. In example 1, why is the formula for % dissociation [A-]/[HA]*100% and not [H3O+]/[HA]*100% or [H3O+][A-]/[HA]*100%? K Direct link to Katie Schleicher's post OH- is actually considere, Posted 6 years ago. We are going to use the Bronsted-Lowry definition of an acid. What carboxylic acid will produce potassium butanoate when it is neutralized by \ ( \mathrm {KOH} \) ? which could follow this experiment. Each mole of HCl reacts with the water to give 1 mole of hydrogen ions and 1 mole of chloride ions. a Direct link to Jonathan Ziesmer's post ICE tables are just a way, Posted 6 years ago. Unit 1: Structures, Trends, Chemical Reactions, Quantitative Chemistry and Analysis, 1.8.3 interpret given data about universal indicator (colour or pH) to classify solutions as acidic, alkaline or neutral and to indicate the relative strengths of acidic and alkaline solutions according to the following classification: pH 02 strong acid, 1.8.7 demonstrate knowledge and understanding that strong acids and strong alkalis are completely ionised in water, recall examples of strong acids (including hydrochloric acid, sulfuric acid and nitric acid) and recall examples of strong alkalis. The experimental determination of pKa values is commonly performed by means of titrations, in a medium of high ionic strength and at constant temperature. / We can see that some of the moles There are a lot of colourless solutions involved, so students will have to be organised. ( Into three of the test tubes place 2 cm depth of ethanoic acid solution (0.05 M). Instead, a new equilibrium constant is defined which leaves it out. Therefore to get the pH we plug the concentration of H 3 O + into the equation pH=-log (0.013745) and get pH=1.86 Example 2: After adding 10 mL of 0.3 M NaOH Question: 1. You can find the percent ionization of a weak base. It is advisable therefore to keep it under teacher control. Any subsequent fires will be very hot and hard to extinguish. You can therefore write a simple expression for the equilibrium constant, K c. Here is the equilibrium again: (5) H A + H 2 O H 3 O + + A + Weak and strong acids - Higher. You can find more information about these and other properties of ethanoic acid atChemguide. Relating Ka and Kb to pH, and calculating percent dissociation. You can assume that [H (aq)] = [HCOO (aq)]. These pages are in completely different parts of this site. This equilibrium constant is a quantitative measure of the strength of an acid in a solution. ThoughtCo, Aug. 26, 2020, thoughtco.com/acid-dissociation-constant-definition-ka-606347. = Is this a stupid question? / K In 1 dm3 of solution, there are going to be about 55 moles of water. [68][69] Buffering is an essential part of acid base physiology including acidbase homeostasis,[70] and is key to understanding disorders such as acidbase disorder. These equations allows us to manipulate acid and base . K Ethanoic acid is a weak acid that of H+ and HCOO, then divide by the equilibrium concentration of HCOOH. Direct link to Hannah McGowen's post Is it possible to find th, Posted 7 years ago. That means that if the concentration of the acid is 0.1 mol dm-3, then the concentration of hydrogen ions is also 0.1 mol dm-3. The lower the pH, the higher the concentration of hydrogen ions in the solution. The hydrochloric acid will show pH = 1, and the ethanoic acid will show pH = 3. (f) The reaction occurs inarigid 4.3 L vessel at 25C, and the total pressure is monitored, as shown in the graph above. Everything is present in the same phase - in this case, in solution in water. here in this generic reaction equation. It is the equilibrium constant for a chemical reaction known as dissociation in the context of acid-base reactions. The weak acid in this question is 1 stronger the acid. A table of pKa of carbon acids, measured in DMSO, can be found on the page on carbanions. They are most quickly and easily represented by the equation: (4) H + ( a q) + O H H 2 O ( l) If you mix dilute ethanoic acid with sodium hydroxide solution, for example, you simply get a colorless solution containing sodium ethanoate. {\displaystyle 1/K_{\mathrm {a} }. Is it a rounding error? K The acid dissociation constant for Calculating the Acid Dissociation Constant of Methanoic Acid Helmenstine, Anne Marie, Ph.D. "Acid Dissociation Constant Definition: Ka." PDF 10 Chemistry of Carbonic Acid Equilibria in Water - Iaea = 8.2: Ionization of Acids in Solution - Chemistry LibreTexts This page titled 8.2: Ionization of Acids in Solution is shared under a CC BY-SA 4.0 license and was authored, remixed, and/or curated by Paul R. Young (ChemistryOnline.com) via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request. Solved 1. Write the IUPAC name for the following: 2. Write - Chegg ( concentration of H+ times the concentration of A divided by the concentration of Calculation of percentage yield (the balanced equation will be given). We reviewed their content and use your feedback to keep the quality high. For the dissociation of ethanoic acid: CH 3 COOH (aq) + H 2 O (l) = CH 3 COO -(aq) + H 3 O +(aq) K a = [CH 3 COO -(aq) ] [H 3 O +(aq)] / [CH 3 COOH (aq) ] Acid Dissociation Constant From pH The acid dissociation constant may be found it the pH is known. Other common strong acids include sulphuric acid and nitric acid. The most tricky area is the formulas of salts of divalent ions with ethanoate. NH -2x or some other number)? internal Does the amount of energy affect the dissociation of methane, Van der Waals constant 'b' for a real gas, Calculating time to reduce alcohol in wine using heating method, Science of Evaporation - General & Personal Questions. Answers and Replies Sep 18, 2004 #2 chem_tr Science Advisor Gold Member 609 3 Most questions answered within 4 hours. [57] A typical procedure would be as follows. Its ionization is shown below. Solved (a) Is pentanoic acid, HC5H11CO2, a strong or weak - Chegg In the following table, the entropy terms are calculated from the experimental values of pKa and H. It is now easy to see the trend towards weaker acids as you go down the table. Acid Dissociation Constant Definition: Ka - ThoughtCo Formic acid | Formula, Preparation, Uses, & Facts | Britannica This will ensure that pKa remains invariant during the titration. In scientific notation and to one What Is an Acid Dissociation Constant, or Ka in Chemistry? used to provide a quantitative measurement of the strength of an acid. 9. pH = . [Total 3 marks] Methanoic acid is a component of a buffer solution used in shampoos. and A ions, then dividing by the equilibrium concentration of the acid. Weak acid-base equilibria (article) | Khan Academy p Most organic acids are weak. 1 Continue to add drops until the pH is neutral. Acids and bases: 8.53 - Acid and base dissociation constants - IB Chem K For example, for, Assume that the quotient of activity coefficients has a numerical value of 1, so that, Express each concentration value as the ratio c/c. Isothermal titration calorimetry (ITC) may be used to determine both a pK value and the corresponding standard enthalpy for acid dissociation. [64]. Direct link to Bibika's post After reading the article, Posted 3 months ago. K Write the IUPAC name for the following: 2. constant for methanoic acid, well need to multiply the equilibrium concentrations The two microconstants represent deprotonation either at sulphur or at nitrogen, and the macroconstant sum here is the acid dissociation constant 1 On right, structure of a generic amine: a neutral nitrogen atom with single bonds to R1, R2, and R3. NH The vessel originally did not containany gas. A calculated titration curve for oxalic acid is shown at the right. In chemistry, an acid dissociation constant (also known as acidity constant, or acid-ionization constant; denoted ) is a quantitative measure of the strength of an acid in solution. Acid dissociation constants can be Acid and Base Ionization Constants | CHEM101 ONLINE: General Chemistry When an acid dissolves in water, a proton (hydrogen ion) is transferred to a water molecule to produce a hydroxonium ion and a negative ion depending on what acid you are starting from. Copyright 2023 NagwaAll Rights Reserved. The dissociation (ionisation) of an acid is an example of a homogeneous reaction. It is also known as Methanoic acid and an important substance for the synthesis of a number of substances. Acids and Bases: Calculating pH of a Strong Acid, Henderson Hasselbalch Equation Definition, Acids and Bases - Calculating pH of a Strong Base, Ph.D., Biomedical Sciences, University of Tennessee at Knoxville, B.A., Physics and Mathematics, Hastings College. An acidic solution, on the other hand, is very hazardous because all the cyanide is in its acid form. This results in Acid Dissociation Constant (K a) for aqueous systems: Ka = [H3O +][A ] [HA] where, Ka = K[H2O] K a is only used for weak acids. start text, A, end text, start superscript, minus, end superscript, K, start subscript, start text, a, end text, end subscript, equals, start fraction, open bracket, start text, H, end text, start subscript, 3, end subscript, start text, O, end text, start superscript, plus, end superscript, close bracket, open bracket, start text, A, end text, start superscript, minus, end superscript, close bracket, divided by, open bracket, start text, H, A, end text, close bracket, end fraction, K, start subscript, start text, a, end text, end subscript, start text, B, H, end text, start superscript, plus, end superscript, K, start subscript, start text, b, end text, end subscript, equals, start fraction, open bracket, start text, B, H, end text, start superscript, plus, end superscript, close bracket, open bracket, start text, O, H, end text, start superscript, minus, end superscript, close bracket, divided by, open bracket, start text, B, end text, close bracket, end fraction, K, start subscript, start text, b, end text, end subscript, start text, H, F, end text, left parenthesis, a, q, right parenthesis, start text, H, B, r, end text, left parenthesis, a, q, right parenthesis, start text, H, A, end text, left parenthesis, a, q, right parenthesis, plus, start text, H, end text, start subscript, 2, end subscript, start text, O, end text, left parenthesis, l, right parenthesis, \rightleftharpoons, start text, H, end text, start subscript, 3, end subscript, start text, O, end text, start superscript, plus, end superscript, left parenthesis, a, q, right parenthesis, plus, start text, A, end text, start superscript, minus, end superscript, left parenthesis, a, q, right parenthesis, start text, H, end text, start superscript, plus, end superscript, open bracket, start text, H, end text, start subscript, 3, end subscript, start text, O, end text, start superscript, plus, end superscript, close bracket, start text, C, end text, start subscript, 4, end subscript, start text, H, end text, start subscript, 6, end subscript, start text, O, end text, start subscript, 5, end subscript, left parenthesis, start text, C, end text, start subscript, 4, end subscript, start text, H, end text, start subscript, 6, end subscript, start text, O, end text, start subscript, 5, end subscript, right parenthesis, K, start subscript, start text, a, end text, end subscript, left parenthesis, 25, degrees, start text, C, end text, right parenthesis, start text, N, H, end text, start subscript, 4, end subscript, start superscript, plus, end superscript, 5, point, 6, times, 10, start superscript, minus, 10, end superscript, start text, H, C, l, O, end text, start subscript, 2, end subscript, 1, point, 2, times, 10, start superscript, minus, 2, end superscript, 7, point, 2, times, 10, start superscript, minus, 4, end superscript, start text, C, H, end text, start subscript, 3, end subscript, start text, C, O, O, H, end text, 1, point, 8, times, 10, start superscript, minus, 5, end superscript, left parenthesis, start text, H, N, O, end text, start subscript, 2, end subscript, right parenthesis, 4, point, 0, times, 10, start superscript, minus, 4, end superscript, 0, point, 400, start text, space, M, end text, start text, H, N, O, end text, start subscript, 2, end subscript, start text, N, O, end text, start subscript, 2, end subscript, start superscript, minus, end superscript, left parenthesis, a, q, right parenthesis, start text, H, N, O, end text, start subscript, 2, end subscript, left parenthesis, a, q, right parenthesis, plus, start text, H, end text, start subscript, 2, end subscript, start text, O, end text, left parenthesis, l, right parenthesis, \rightleftharpoons, start text, H, end text, start subscript, 3, end subscript, start text, O, end text, start superscript, plus, end superscript, left parenthesis, a, q, right parenthesis, plus, start text, N, O, end text, start subscript, 2, end subscript, start superscript, minus, end superscript, left parenthesis, a, q, right parenthesis, K, start subscript, start text, a, end text, end subscript, equals, start fraction, open bracket, start text, H, end text, start subscript, 3, end subscript, start text, O, end text, start superscript, plus, end superscript, close bracket, open bracket, start text, N, O, end text, start subscript, 2, end subscript, start superscript, minus, end superscript, close bracket, divided by, open bracket, start text, H, N, O, end text, start subscript, 2, end subscript, close bracket, end fraction, equals, 4, point, 0, times, 10, start superscript, minus, 4, end superscript, open bracket, start text, H, end text, start superscript, plus, end superscript, close bracket, open bracket, start text, N, O, end text, start subscript, 2, end subscript, start superscript, minus, end superscript, close bracket, start text, H, N, O, end text, start subscript, 2, end subscript, left parenthesis, a, q, right parenthesis, start text, H, end text, start subscript, 3, end subscript, start text, O, end text, start superscript, plus, end superscript, start text, N, O, end text, start subscript, 2, end subscript, start superscript, minus, end superscript, 0, point, 400, start text, M, end text, minus, x, K, start subscript, start text, a, end text, end subscript, equals, start fraction, left parenthesis, x, right parenthesis, left parenthesis, x, right parenthesis, divided by, left parenthesis, 0, point, 400, start text, M, end text, minus, x, right parenthesis, end fraction, equals, 4, point, 0, times, 10, start superscript, minus, 4, end superscript, start fraction, x, squared, divided by, 0, point, 400, start text, M, end text, minus, x, end fraction, equals, 4, point, 0, times, 10, start superscript, minus, 4, end superscript, x, equals, 0, point, 0126, start text, space, M, end text, open bracket, start text, N, O, end text, start subscript, 2, end subscript, start superscript, minus, end superscript, close bracket, equals, open bracket, start text, H, end text, start subscript, 3, end subscript, start text, O, end text, start superscript, plus, end superscript, close bracket, equals, 0, point, 0126, start text, space, M, end text, start text, B, end text, left parenthesis, a, q, right parenthesis, plus, start text, H, end text, start subscript, 2, end subscript, start text, O, end text, left parenthesis, l, right parenthesis, \rightleftharpoons, start text, B, H, end text, start superscript, plus, end superscript, left parenthesis, a, q, right parenthesis, plus, start text, O, H, end text, start superscript, minus, end superscript, left parenthesis, a, q, right parenthesis, 1, point, 50, start text, space, M, end text, start text, N, H, end text, start subscript, 3, end subscript, left parenthesis, K, start subscript, start text, b, end text, end subscript, equals, 1, point, 8, times, 10, start superscript, minus, 5, end superscript, right parenthesis, open bracket, start text, O, H, end text, start superscript, minus, end superscript, close bracket, start text, N, H, end text, start subscript, 3, end subscript, left parenthesis, a, q, right parenthesis, plus, start text, H, end text, start subscript, 2, end subscript, start text, O, end text, left parenthesis, l, right parenthesis, \rightleftharpoons, start text, N, H, end text, start subscript, 4, end subscript, start superscript, plus, end superscript, left parenthesis, a, q, right parenthesis, plus, start text, O, H, end text, start superscript, minus, end superscript, left parenthesis, a, q, right parenthesis, K, start subscript, start text, b, end text, end subscript, equals, start fraction, open bracket, start text, N, H, end text, start subscript, 4, end subscript, start superscript, plus, end superscript, close bracket, open bracket, start text, O, H, end text, start superscript, minus, end superscript, close bracket, divided by, open bracket, start text, N, H, end text, start subscript, 3, end subscript, close bracket, end fraction, equals, 1, point, 8, times, 10, start superscript, minus, 5, end superscript, open bracket, start text, N, H, end text, start subscript, 4, end subscript, start superscript, plus, end superscript, close bracket, start text, N, H, end text, start subscript, 3, end subscript, left parenthesis, a, q, right parenthesis, start text, O, H, end text, start superscript, minus, end superscript, 1, point, 50, start text, M, end text, minus, x, K, start subscript, start text, b, end text, end subscript, equals, start fraction, left parenthesis, x, right parenthesis, left parenthesis, x, right parenthesis, divided by, 1, point, 50, start text, M, end text, minus, x, end fraction, equals, 1, point, 8, times, 10, start superscript, minus, 5, end superscript, start fraction, x, squared, divided by, 1, point, 50, start text, M, end text, minus, x, end fraction, equals, 1, point, 8, times, 10, start superscript, minus, 5, end superscript, x, equals, open bracket, start text, O, H, end text, start superscript, minus, end superscript, close bracket, equals, 5, point, 2, times, 10, start superscript, minus, 3, end superscript, start text, space, M, end text, start text, p, H, end text, plus, start text, p, O, H, end text, equals, 14, start text, p, H, end text, equals, 14, minus, start text, p, O, H, end text, start text, p, H, end text, equals, 14, point, 00, minus, left parenthesis, 2, point, 28, right parenthesis, equals, 11, point, 72, start text, C, end text, start subscript, 5, end subscript, start text, H, end text, start subscript, 5, end subscript, start text, N, end text, 1, point, 7, times, 10, start superscript, minus, 9, end superscript, 2, point, 6, times, 10, start superscript, minus, 20, end superscript, 3, point, 8, times, 10, start superscript, minus, 10, end superscript.