# Analysis Of Ka And Pkb

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DETERMINATION OF pKa AND pKb USING ACID-BASE TITRATIONS
Introduction
Acid-base titrations can be used to determine pKa of a weak acid and pKb of a base. A weak acid and a weak base incompletely dissociate in water. For this reason, the concentration of hydrogen ions (H+) and hydroxide ions (OH-) depend on equilibrium coefficients of acid (Ka) and base (Kb). Equation 1 shows the chemical dissociation equation of a weak acid. Furthermore, Equation 2 describes the equilibrium constant of a weak acid. On the other hand, Equation 3 and Equation 4 illustrate the chemical equation for the dissociation and equilibrium constant of a weak base.
HA ↔ H+ + A-…………………………………………………. Equation 1
Ka=[H+][A-]/[HA]……………………………………………… Equation 2
BH+ + OH-↔ B + H2O………………………………………… Equation 3
Kb= [B+][OH-]/[BOH]…………………………………………. Equation 4
The equilibrium constants (Ka and Kb) are intrinsic properties of a particular weak/base pair. Ka defines the manner in which conjugate base holds on to the H+ (proton) while Kb describes the ‘stickiness’ of a weak acid for hydroxide ions(OH-). Taking the logarithm of
For acetic acid-sodium hydroxide titration, 10ml of distilled water was added to 250ml Erlenmeyer flask. 20ml of diluted acetic acid was pipetted into that 250ml Erlenmeyer flask. Titration system that contained 0.100M NaOH in the burette was set up. The pH meter was used to monitor pH of the system when sodium hydroxide was being added. NaOH was added in an increment of 1ml until the pH of the solution reached 4.8. After the solution reached pH of 4.8, NaOH was added in increment of 0.1ml until the solution passed its equivalence point. NaOH was added in an increment of 1ml after equivalence point until there was an insignificant change in solution pH when titrant was added. Values of pH and titrant used were recorded and used in drawing titration

• ## Henderson-Hasselbalch Analysis Lab

The determination of the pH of a buffer solution and the pKa for of a weak acid Introduction A practical was carried out to show how the Henderson-Hasselbalch equation works and to apply and hone the skills of pipetting, buffer-making, pH-meter use and graphing. The primary goal of the practical was to determine the pKa value of a weak acid. The Ka is an acid dissociation constant, it is a quantitative measure of the strength of an acid in solution. The pKa is defined as the negative log of the Ka, pKa= -log Ka. The lower the value for the pKa the more acidic the acid (greater concentration of H+ ions).…

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• ## Acid Base Titrations II: Potentiometric And Indicator T

Next, 25mL of 0.1 M Acetic acid is pipetted into a 100mL beaker. The 0.1 M Acetic acid is titrated with the 0.1 M NaOH in increments given in the data sheet; mixing well at each point and wait until the pH stabilizes. The pH is recorded at each increment and the electrode is rinsed with distilled water and placed back in the beaker with distilled water. Then, 25mL of 0.1 M Acetic acid is pipetted into a 250mL Erlenmeyer flask. Next, 2-3 drops of the proper indicator is added.…

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• ## Thin Layer Chromatography

A 50 mL flask was weighed and recorded. A separation funnel was then filled with 10mL of 3M NaOH and 10 mL of the dichloromethane. The funnel was capped and flipped upside-down while the lid was held. The solvent was mixed inside the separation funnel for a couple…

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The acidic phthalimide molecule gets deprotonated by a strong base. The strength of an acid depends on the stability of the conjugate base. The negative charge on the conjugate base of phthalimide is delocalised over three highly electronegative oxygen and nitrogen atoms. The combined electron-withdrawing resonance and inductive effect ensures that the negative charge on the nitrogen atom is effectively dispersed. Step 2: nucleophilic substitution In Section 3.6 Halogen Derivatives, it was mentioned that an alkyl halide can undergo nucleophilic substitution by heating with excess alcoholic ammonia to yield a primary amine.…

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• ## The Correlation Between Doolittle's Values And Solubility

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• ## Thermodynamics Of Potassium Nitrate Dissolving In Water Essay

Set up a hot plate and place a 400-mL beaker filled half-way with tap water. 2. Use a balance to weigh out 10 g of KNO3 on weighing paper. Place the KNO3 from the weighing paper into the 25 * 200 mm test tube. 3.…

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• ## Potentiodynamic Polarisation Test Of Mg Znn-N-Zn-Xca Alloys

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