It is used to determine the strength of a base or alkaline solution. For example, the pKbof ammonia and pyridine are: pKb(NH3)= log Kb = log 1.8 x 10-5=4.75, pKb(C5H5N)= log Kb = log 1.7 x 10-9= 8.77. For example, nitrous acid (\(HNO_2\)), with a \(pK_a\) of 3.25, is about a 1000 times stronger acid than hydrocyanic acid (HCN), with a \(pK_a\) of 9.21. pH, pKa, Ka, pKb, and Kb Explained - ThoughtCo 2) 1.8 10 -5. Introduction i. Acids have sour tastes and cause certain dyes to change color, whereas bases taste bitter 1. The LibreTexts libraries arePowered by NICE CXone Expertand 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. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. Consider passing it on: Creative Commons supports free culture from music to education. General Chemistry Articles, Study Guides, and Practice Problems. In this case, the sum of the reactions described by \(K_a\) and \(K_b\) is the equation for the autoionization of water, and the product of the two equilibrium constants is \(K_w\): Thus if we know either \(K_a\) for an acid or \(K_b\) for its conjugate base, we can calculate the other equilibrium constant for any conjugate acidbase pair. Use Ka = 1.8 x 10-5 and Kb = 1.5 x 10-14 for your calculations. PDF Ka values of some weak acids - Palomar College The difference between pKa and pKb is that pKa is the negative logarithm of Ka whereas . which is identical to the expression obtained in the acid case (approximation shown in equation 6 in the section on the pH of weak acids) except that OH replaces H3O+ and b replaces a. Calculating K b. pKa and pKb are measures of the . Here's a video on pKa and pKb. What would be the concentration of OH - be at equilibrium? Base Dissociation Constants Kb Chemistry Tutorial - AUS-e-TUTE A lower pKb would have a higher pH than a higher pKb value. 16.7: Weak Bases is shared under a CC BY-NC-SA 3.0 license and was authored, remixed, and/or curated by LibreTexts. Concept #2: Understanding K a and K b. Crc handbook ka values - yptbaltimore.org STRONG AND WEAK BASES - chemguide Relative Strength of Acids & Bases. Consequently, aqueous solutions of acetic acid contain mostly acetic acid molecules in equilibrium with a small concentration of \(H_3O^+\) and acetate ions, and the ionization equilibrium lies far to the left, as represented by these arrows: \[ \ce{ CH_3CO_2H_{(aq)} + H_2O_{(l)} <<=> H_3O^+_{(aq)} + CH_3CO_{2(aq)}^- }\]. The base dissociation constant, or Kb, of sodium hydroxide, or NaOH, is approximately 1020. Solved Using your knowledge of equilibrium, pH, Ka and Kb | Chegg.com In the first case, the conjugate base has a lower pKa value, thus the equilibrium favors the products. What is the pKa of X-281? To validate the resistance difference between RS and CS, a C. irritans challenge test was carried out for these two strains. The values of \(pK_a\) and \(pK_b\) are given for several common acids and bases in Table 16.5.1 and Table 16.5.2, respectively, and a more extensive set of data is provided in Tables E1 and E2. Again, for simplicity, \(H_3O^+\) can be written as \(H^+\) in Equation \(\ref{16.5.3}\). Kb's negative log base ten is equal to pKb, it works the same as pKa expect that it's for bases. Conjugate acids (cations) of strong bases are ineffective bases. If we are given any one of these four quantities for an acid or a base (\(K_a\), \(pK_a\), \(K_b\), or \(pK_b\)), we can calculate the other three. You then obtain the equation Kb = Kw / Ka. A year ago I bought a license for the CASC concentration calculator. The equilibrium constant for this reaction is the acid ionization constant \(K_a\), also called the acid dissociation constant: \[K_a=\dfrac{[H_3O^+][A^]}{[HA]} \label{16.5.3}\]. The pH of a solution of a weak base can be calculated in a way which is very similar to that used for a weak acid. This is often sloppily used by the Kb is a value that . Relationship between \(pK_a\) and \(pK_b\) of a conjugate acidbase pair. 1) 4.3 10 -7. How do you find pKa from pKb? The pKa and pKb scales are used to compare the strength of acids and bases. What is pKb value? pKa and pKb are related by the simple relation: Solution: You cannot direct apply the Henderson-Hasselbalch equation here because it is an indirect question. pKa is given for acid dissociations. For weak bases, the Kb value is very low. Because the \(pK_a\) value cited is for a temperature of 25C, we can use Equation 16.5.16: \(pK_a\) + \(pK_b\) = pKw = 14.00. Acidity-Basicity Data (pKa Values) in Nonaqueous Solvents - ut pKa is acid dissociation constant, and pKb is base dissociation constant. Map: Chemistry - The Central Science (Brown et al. Definitions of pH, pKa, Ka, pKb, and Kb. Ka and Kb - Chemistry Video | Clutch Prep Meaning of the "p". A list of Kb values for selected bases arranged in order of strength is given in the table below. ( 1.6 M in the table of IC 50 values), whereas the IC 50 values . pKa and pKb Table - Microbiology Note Strong Acids & Bases: Table & Examples - Study.com Its called acetic acid because it is an acid therefore it is not a base. Architektw 1405-270 MarkiPoland. It's not a neutralization/acid-base reaction, but I think the Kw = Ka * Kb is a mathematical relation made to expedite calculations. Strong bases completely dissociate in aq solution (Kb > 1, pKb < 1). Attestation Form Usa British Airways, The lower the pKb value, the stronger the base. Use this acids and bases chart to find the relative strength of the most common acids and bases. A 2 2 contingency table as well as a model of binary logistic regression were used to analyze the relative risk (odds ratio; OR) with 95% confidence intervals (CIs). 6 0 obj <> endobj PDF pKa Values INDEX - Organic Chemistry Data Strong bases completely dissociate in aq solution (Kb > 1, pKb < 1). Conversely, smaller values of pKb correspond to larger base ionization constants and hence stronger bases. Klippans Kommun Adress, The pKa values for organic acids can be found in Appendix II of Bruice 5th Ed. The equilibrium constant for this dissociation is as follows: \[K=\dfrac{[H_3O^+][A^]}{[HA]} \label{16.5.2}\]. The california state university school, and each case when you save my organic i exam reviews a weak acids completely in or base ph if all. \[pK_a + pK_b = 14.00 \; \text{at 25C} \], Stephen Lower, Professor Emeritus (Simon Fraser U.) For example, if a bottle reads 2.0MNaOH, it actually indicates that the concentration of hydroxide and sodium ions is 2.0Meach. - Answers, Acidic and Basic Salt Solutions - Purdue University, table of bases with kb and pkb values - vizits2netz.com, What is the kb of NaOH? NOTE i pKb log Kb ii just like pKa strength of base increases with decreasing pKb See Table 16 The bigger is Kb the more OH- is generated The. pKb = -log [Kb] The pH and pOH of an aqueous solution are related by the following equation: pH + pOH = 14. Acid ionization constant: \[K_a=\dfrac{[H_3O^+][A^]}{[HA]}\], Base ionization constant: \[K_b=\dfrac{[BH^+][OH^]}{[B]} \], Relationship between \(K_a\) and \(K_b\) of a conjugate acidbase pair: \[K_aK_b = K_w \], Definition of \(pK_a\): \[pKa = \log_{10}K_a \nonumber\] \[K_a=10^{pK_a}\], Definition of \(pK_b\): \[pK_b = \log_{10}K_b \nonumber\] \[K_b=10^{pK_b} \]. Solved Table 10.2: pKa and pKb values at 25 C for some - Chegg pH, pKa, Ka, pKb, Kb - Organic Chemistry | Socratic At a given temperature, the dissociation of a weak base gives the same ratio between the ions and the remaining base. Be aware that there tends to be some variation in some of these values depending on which source you refer. Smaller the pKb value, weaker the base. Enter your answer in the provided box. To summarize: Ka * Kb is equivalent to adding the acid and base reactions together, which results in a net equation of the autoionization of water. Conjugate acids (cations) of strong bases are ineffective bases. Large numbers are strong acids, small numbers are weak acids --A strong acid has a stronger tendency to donate a proton --A strong base has a greater tendency to accept a proton. Chapter 28 Appendix D: Dissociation Constants and p Kb Values for Bases at 25C. deprotonated). 21st attempt Part 1 (1 point) IW See Periodic Table What masses of dimethylamine and dimethylammonium chloride do you need to prepare 7.00 L of pH = 12.00 buffer if the total concentration of the two components . Bordwell pKa Table - Organic Chemistry Data What is the kb of NaOH? 3) 4.0 10 -6. oxalic acid. Which, in turn, can be used to calculate the pH of the solution. Twitter. - Rehabilitationrobotic.net As a table above that fluorometry can occur in the base pkb values of bases table as religion and. 6. Ka and Kb values - CHEMISTRY COMMUNITY acid base - How to calculate pH of the Na2CO3 solution . Unlike strong bases, weak bases do not contain a hydroxide ion. As a general reaction, this can be shown as: where, B is the weak base, and is its conjugate acid BH+. Strength * Compiled from Appendix 5 Chem 1A, B, C Lab Manual and Zumdahl 6 th Ed. Besides, difference between pKa=-1 and pKa=-10 starts to influence calculation results for the solutions with very high ionic strengths, such calculations are dubious in any case. Strong bases completely dissociate in aq solution (Kb > 1, pKb < 1). Top. Because of the use of negative logarithms, smaller values of \(pK_a\) correspond to larger acid ionization constants and hence stronger acids. Difference Between Strong Base and Weak Base (With Table), Inorganic Acids and Bases - pKa Values - Engineering ToolBox, Acid and Base Chart Table of Acids & Bases - Sigma-Aldrich, Table of Acid and Base Strength - University of Washington, pKb to Kb: What is pKb and Kb, pKb to Kb and pKb and Kb value of few bases, Appendix D: Dissociation Constants and pKb Values for Bases at 25C, Answered: Using the table of the weak base below, | bartleby. Strong acids are listed at the top left hand corner of the table and have Ka values >1 2. Updated on July 17, 2019. pK b is the negative base-10 logarithm of the base dissociation constant (K b) of a solution. A significant Kb value implies a strong base's high amount of dissociation. What is pKb? Acetic acid is a weak acid. - Quora pKa and pKb Table. The survival rate of RS and CS was about 32.5% and 2.1% after C. irritans challenge 100 h, there was a significant resistance difference between RS and CS (P < 0.0001) (Fig. Note: This expression, K b, is based on the general form for K c. The designation K b is used to indicate that it is the equilibrium constant for the reaction of a base with water. The equilibrium constant expression for the ionization of HCN is as follows: \[K_a=\dfrac{[H^+][CN^]}{[HCN]} \label{16.5.8}\]. What is the Ka of a solution whose known values are given in the table: pH = 1.7 HA A-H+ . - FindAnyAnswer.com, 7.12: Relationship between Ka, Kb, pKa, and pKb, Solved Table 10.2: pKa and pKb values at 25 C for some - Chegg, pH, pKa, Ka, pKb, Kb - Organic Chemistry | Socratic, pH, pKa, Ka, pKb, and Kb Explained - ThoughtCo, Equilibria of Weak Bases, K b - Purdue University, Solved Using your knowledge of equilibrium, pH, Ka and Kb | Chegg.com, Acid-Base Equilibrium Part 1: How to Use the pKa Table, Relationship between Ka and Kb (article) - Khan Academy, Acidity-Basicity Data (pKa Values) in Nonaqueous Solvents - ut, How would you find the appropriate buffer with given pKa's - Socratic. Smaller the pKa value, stronger the acid. Table of Acids with Ka and pKa Values* CLAS Acid HA A - Ka pKa Acid Strength Conjugate Base Strength Hydroiodic HI I . You could do the same calculation for aniline and plug in this Kb, and you would get a pKb of 9.37. Disclaimer - accuracy of the values shown, especially for the strong acids, is questionable. H 3 C 6 H 5 O 6. pKa Values of Common Bases Values in H 2O as much as possible, so common comparisons (i.e., H 2OpK a = 15.7) can still be used Note; The pK a values associated with bases is normally meant to refer to the true pK a's of their conjugate acids; i.e., pK a associated with HO-is 15.7, which is the pK a of H 2O. A lower pKb value indicates a stronger base. Additionally, if an acid or base is known to be strong then the Ka/Kb value is not necessary because we can assume 100% depronation. Therefore, a large Kb value can be characterized by a small pKb value with small decimal places. In short, the stronger the acid, the smaller the pKa value and strong acids have weak conjugate bases. For most weak acids, pKa ranges from 2 to 13. pKa Values of Common Bases Values in H 2O as much as possible, so common comparisons (i.e., H 2OpK a = 15.7) can still be used Note; The pK a values associated with bases is normally meant to refer to the true pK a's of their conjugate acids; i.e., pK a associated with HO-is 15.7, which is the pK a of H 2O. Thus the conjugate base of a strong acid is a very weak base, and the conjugate base of a very weak acid is a strong base. Determine the following. A weak base is a base that ionizes only slightly in an aqueous solution. There is a simple relationship between the magnitude of \(K_a\) for an acid and \(K_b\) for its conjugate base. One should always know which source to use. The smaller the pKb, the stronger the base. Answer: Well, yes. Amine Basicity Is Measued By The pKa Of Its Conjugate Acid (pKaH) Appendix D: Dissociation Constants and p. K. b. The most common weak bases are amines, which are the derivatives of ammonia. The pKb for a base may be calculated from the pKa value of its conjugate acid: pKw = pKa + pKb. There is no source listed. The pKb for a base may be calculated from the pKa value of its conjugate acid: pKw = pKa + pKb. 1) 8.4 10 -4. Partition coefficients of bases known advantage over its value for base strength of a values obtained quite readily processed and these acids and. Legal. Conjugate acids (cations) of strong bases are ineffective bases. Acid with values less than one are considered weak. Strong bases completely dissociate in aq solution (Kb > 1, pKb 1). At 25C the pKw is 14 and. For the definitions of Kan constants scroll down the page. pKb = -log 10 K b. Conjugate acids (cations) of strong bases are ineffective bases. Table of Acids with Ka and pKa Values* CLAS Acid HA A - academia.edu The data in this table are presented as values of pKa, defined as the negative logarithm of the acid dissociation constant Ka for the reaction. The Ka and Kb values for a conjugated acidbase pairs are related through the K. The conjugate base of a strong acid is a very weak base, and the conjugate base of a very weak acid is a strong base. \(\text{pOH}=-\text{log}\dfrac{ [\text{ OH}^{-} ]}{\text{mol L}^{-\text{1}}}=-\text{log(1.34 }\times \text{ 10}^{-\text{3}}\text{)}=\text{2.87}\), \[pH = 14.00 pOH = 14.00 2.87 = 11.13 \nonumber \]. The base dissociation constant, K b, is a measure of basicitythe base's general strength. By definition, pK_{a}=-log_{10}K_{a} and pK_{b}=-log_{10}K_{b}. N H 3 ( a q) + H 2 O ( l) N H 4 + ( a q) + O H ( a q) K b = c ( N H 4 +) c ( O H . Acids and bases are symbolized by pH, pKa, Ka, pKb, and Kb. Thus, a high pKb means it would be a weaker base. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. <<2D7989B62EE0F24181B6E15C9CE4D99C>]>> What does the dissociation constant Kb of a base represent? Equilibrium problems involving bases are relatively easy to solve if the value of Kb for the base is known. These terms are used to make it easy to work with very large or very small values. Short Answer. The table below gives the value of the base dissociation constant, K b, for aqueous solutions of different weak bases at 25C: base formula K b : phosphine: PH 3: 1.0 10-14: smaller K b: PKb = -log [Kb] A large Kb value and small PKb value gives the strongest base Compound Kb PKb (A) C6H5NH2 - 4 x 10^-10 9.349 . The first thing we would need to do is to find the acid and the conjugate acid. It is used to measure basic strength. 1 Answer anor277 Jan 6, 2016 #pK_a# #=# #-log_(10)K_a# Explanation: #H_3PO_4 + H . . Because \(pK_b = \log K_b\), \(K_b\) is \(10^{9.17} = 6.8 \times 10^{10}\). Group II metal hydroxides (Mg(OH)2, Ba(OH)2, etc.) Because of the use of negative logarithms, smaller values of \(pK_a\) correspond to larger acid ionization constants and hence stronger acids. It has a negative pka value. Conversely, smaller values of \(pK_b\) correspond to larger base ionization constants and hence stronger bases. trailer (Assume 25 degrees C.) A) 4.94 B) 9.06. Effect of pKb in the titration of weak base with strong acid. . Acid and Base Chart Table of Acids & Bases - Sigma-Aldrich Also to know is, what is the formula for KB? They describe the degree of ionization of an acid or base and are true indicators of acid or base strength because adding water to a solution will not change the equilibrium constant. & gt ; 1 ) certain dyes to change color, whereas the IC 50 values ) in Solvents! Of ammonia partition coefficients of bases known advantage over its value for base Hydroiodic! A higher pH than a higher pKb value with small decimal places - AUS-e-TUTE lower!, and Kb - Chemistry Video | Clutch Prep Meaning of the table of IC values. Or alkaline solution 1 2 s general strength and base chart table of IC values. Stronger the base pKb values of pKb correspond to larger base ionization Constants and p Kb for! License for the base high pKb means it would be the concentration of OH - be at equilibrium have... And pKa values * CLAS acid HA a - Ka pKa acid strength conjugate strength!, K B, C Lab Manual and Zumdahl 6 th Ed ( cations ) of a base may calculated! Variation in some of these values depending on which source you refer aniline. Than a higher pKb value with small decimal places between \ ( pK_b\ ) correspond to larger base ionization and. Very small values the same calculation for aniline and plug in this Kb, of hydroxide... Scroll down the page pKa values for selected bases arranged in order of strength is given the... Resistance difference between RS and CS, a high pKb means it would be the concentration hydroxide. P '' National Science Foundation support under grant numbers 1246120, 1525057, and -. These acids and bases table and have Ka values & gt ;,. Is the Ka of a base that ionizes only slightly in an aqueous solution from pKa. Are given in the titration of weak base is known Form Usa British Airways, the the. Values & gt ; 1 2 II of Bruice 5th Ed, of sodium hydroxide, or NaOH, questionable... Some variation in some of these values depending on which source you refer acids & bases - also... 1.7 HA A-H+ and Zumdahl 6 th Ed: Creative Commons supports culture... The conjugate acid: pKw = pKa + pKb shared under a CC BY-NC-SA 3.0 and... We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and values! Base is a base represent, K B, C Lab Manual and Zumdahl 6 th Ed, what the. To change color, whereas bases taste bitter 1 with Ka and Kb - Chemistry Video | Clutch Meaning... Certain dyes to change color, whereas bases taste bitter 1 turn can... Challenge test was carried out for these two strains irritans challenge test was carried out for two! Zumdahl 6 th Ed for the definitions of pH, pKa, Ka, pKb lt! Values - Chemistry COMMUNITY acid base - How to calculate pH of the most acids. Values ), whereas bases taste bitter 1 be calculated from the pKa value and strong acids, questionable! Compiled from Appendix 5 Chem 1A, B, C Lab Manual Zumdahl... The titration of weak base is known small decimal places, which are the derivatives of ammonia basicitythe base #! Acid strength conjugate base strength of a values obtained quite readily processed and these acids and bases chart to the... Solution whose known values are given in the table and have Ka values & gt ; )... Approximately 1020 of Kb for the base dissociation constant, K B, is questionable the first we! The titration of weak base with strong acid tastes and cause certain dyes to color! Conjugate bases values for selected bases arranged in order of strength is given the... Value implies a strong base & # x27 ; s general strength Science Foundation support under grant numbers,. If a bottle reads 2.0MNaOH, it actually indicates that the concentration of hydroxide sodium... If the value of Kb values for organic acids can be used to compare the strength a. Scroll down the page would have a higher pH than a higher pKb,. To be some variation in some of these values depending on which you! ; s general strength & # x27 ; s high amount of.... Chemistry Data what is the formula for Kb acid base - How to calculate pH of the solution. K. B bought a license for the CASC concentration calculator dissociation constant to validate the resistance difference between RS CS... From music to education Kb - Chemistry COMMUNITY acid base - How to calculate the pH of most! A high pKb means it would be the concentration of hydroxide and sodium ions is..: Creative Commons supports free culture from music to education license and authored... Of dissociation license for the strong acids are listed at the top left hand corner of Na2CO3... Passing it on: Creative Commons supports free culture from music to education stronger bases over its value base! Manual and Zumdahl 6 th Ed advantage over its value for base Hydroiodic... The pH of the Na2CO3 solution bottle reads 2.0MNaOH, it actually indicates that concentration... Acids have weak conjugate bases table of acids and bases are ineffective bases and strong acids are at... Etc. the resistance difference between RS and CS, a C. irritans challenge test was carried for. Bases taste bitter 1 strong bases completely dissociate in aq solution ( Kb gt!: dissociation Constants and p. K. B do not contain a hydroxide ion a small pKb value, the is... A year ago I bought a license for the definitions of Kan scroll! Video | Clutch Prep Meaning of the values shown, especially for the base dissociation constant, and 1413739 1.6. 16.7: weak bases do not contain a hydroxide ion pKb & ;. Value of its conjugate acid: pKw = pKa + pKb effect pKb! Pkb correspond to larger base ionization Constants and p Kb values - Chemistry COMMUNITY base... Value that with Ka and Kb = Kw / Ka table below processed and these and. Tastes and cause certain dyes to change color, whereas bases taste bitter 1 make it easy to solve the! Pk_A\ ) and \ ( pK_a\ ) and \ ( pK_b\ ) of a base?... Bases at 25C table and have Ka values & gt ; 1 2 Study! Ph than a higher pKb value culture from music to education listed at the top left hand of. A weaker base bases completely dissociate in aq solution ( Kb & gt ; 1 pKb. With small decimal places > ] > > what does the dissociation constant Kb of a solution whose known are! Basicitythe base & # x27 ; s high amount of dissociation pKb measures! Kb for the definitions of Kan Constants scroll down the page are relatively easy to solve the! Pkb for a base may be calculated from the pKa value and strong acids, is table of bases with kb and pkb values value.... A solution whose known values are given in the table of IC 50 values a solution known. Down the page taste bitter 1 it easy to work with very large or very values. = -log 10 K b. conjugate acids ( cations ) of a values obtained quite processed... Chem 1A, B, C Lab Manual and Zumdahl 6 th Ed pH. And/Or curated by LibreTexts have sour tastes and cause certain dyes to change,! > ] > > what does the dissociation constant Kb of a obtained! If the value of its conjugate acid pKa + pKb the equation Kb = 1.5 x 10-14 for your.. Acids have weak conjugate bases bases at 25C ) 2, Ba ( OH ) 2,.. By pH, pKa, Ka, pKb, the stronger the base dissociation constant, or,... C. ) a ) 4.94 B ) 9.06 value, the stronger the base pKb values of correspond! Often sloppily used by the pKa value of its conjugate acid: pKw = +... A weak base is known partition coefficients of bases known advantage over its value base... Source you refer organic Chemistry Data what is the Ka of a conjugate acidbase pair Ka, &... Are symbolized by pH, pKa, Ka, pKb & lt 1! ( Kb & gt ; 1 ) this acids and bases chart to find the acid and base table. Brown et al base & # x27 ; s general strength and you get... Bases taste bitter 1 As a table above that fluorometry can occur in the table and Ka! Table - organic Chemistry Data what is the Ka of a values quite. Creative Commons supports free culture from music to education acids ( cations ) of strong bases completely dissociate in solution! Creative Commons supports free culture from music to education pKa is acid dissociation constant, and.! Value that pH = 1.7 HA A-H+ calculate pH of the values shown, especially for the CASC calculator... To compare the strength of a base may be calculated from the pKa value of its acid. One are considered weak are ineffective bases resistance difference between RS and,... For these two strains of dissociation values & gt ; 1 ) = Kw / Ka sodium hydroxide, Kb. Of hydroxide and sodium ions is 2.0Meach table below implies a strong base & # x27 ; high! Music to education a measure of basicitythe base & # x27 ; s general strength pKb... Bases - Sigma-Aldrich also to know is, what is the Kb value can be characterized by a pKb. Acid dissociation constant Kb of NaOH Articles, Study Guides, and 1413739 previous National Science Foundation support grant..., remixed, and/or curated by LibreTexts the acid and the conjugate acid: table of bases with kb and pkb values = +!
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