Potassium hydrogen phthalate determination

When standardizing a solution of NaOH against potassium hydrogen phthalate (KHP), a variety of systematic and random errors are possible. Identify, with justification, whether the following are systematic or random sources of error, or if they have no effect. If the error is systematic, then indicate whether the experimentally determined molarity for NaOH will be too high or too low. The standardization reaction is... 

A titration requires a solution whose concentration is known. In Example the NaOH solution used as the titrant was known to be 0.1250 M. A titrant of known concentration is known as a standard solution, and the concentration of such a solution is determined by a standardization titration. In a standardization titration, the solution being titrated contains a known amount of acid or base. An excellent acid for standardization is potassium hydrogen phthalate, KHCg H4 O4. This substance, a carboxylic acid that contains one weakly acidic hydrogen atom per molecule, is easily obtained as a highly pure solid. A known number of moles can be weighed on an... 

C04-0157. As a final examination in the general chemistry laboratory, a student was asked to determine the mass of Ca (0H)2 that dissolves in 1.000 L water. Using a published procedure, the student did the following (1) About 1.5 mL of concentrated HCl (12 M) was added to 750 mL of distilled water. (2) A solution of KOH was prepared by adding approximately 1.37 g KOH to 1.0 L distilled water. (3) A sample of potassium hydrogen phthalate (185.9 mg) was dissolved in 100 mL of distilled water. Titration with the KOH solution required 25.67 mL to reach the stoichiometric point. (4) A 50.00-mL sample of the HCl solution prepared in step 1 was titrated with the KOH solution. The titration required 34.02 mL of titrant to reach the stoichiometric point. (5) The student was given a 25.00-mL sample of a saturated solution of Ca (0H)2 for analysis. Titration with the HCl solution required 29.28 mL to reach the stoichiometric point. How many grams of calcium hydroxide dissolve in 1.00 L of water ... 

Potassium hydrogen phthalate has many uses in analytical chemistry. It is a primary standard for standardization of bases in aqueous solutions. Its equivalent weight is 204.2. It also is a primary standard for acids in anhydrous acetic acid. Other applications are as a buffer in pH determinations and as a reference standard for chemical oxygen demand (COD). The theoretical COD of a Img/L potassium hydrogen phthalate is 1.176mg O2. 

Potassium hydrogen phthalate (KHP) is used as a reference standard for COD analysis. The theoretical COD for 1 mg KHP is 1.175 mg, which is determined from either of the following equations ... 

Potassium hydrogen phthalate, known as KHP (molar mass = 204.22 g/mol), can be obtained in high purity and is used to determine the concentration of solutions of strong bases by the reaction... 

For determinations of reaction constants, anomeric purity is not necessary, but for the determination of initial rotations, only one anomer can be present. Pure anomers can often be obtained by slow crystallization from a suitable solvent in the presence of nucleating crystals of the desired form and in the absence of crystals of other forms. For measurements in aqueous solution, use of mM potassium hydrogen phthalate as a buffer (pH 4.4) is recommended, to avoid variation in acidity during measurements. Precautions for purification, drying, and use of organic solvents have been described by Lowry and Baker. Anomeric impurities can be removed by lixiviation with a solvent (such as aqueous alcohol) in which both anomers are slightly soluble. 

We have made other kinds of errors in our analytical determinations. For instance many of us have been measuring the pH of seawater using equipment calibrated by 0.050M potassium hydrogen phthalate. Have we really been measuring pH The answer is no, and the meaning of our measurements is just beginning to be understood and with it the effects of salinity, temperature, and pressure. 

A student carries out an experiment to standardize (determine the exact concentration of) a sodium hydroxide solution. To do this, the student weighs out a 1.3009-g sample of potassium hydrogen phthalate (KFIC8FI4O4, often abbreviated KHP). KFIP (molar mass 204.22 g/mol) has one acidic hydrogen. The student dissolves the KHP in distilled water, adds phenolphthalein as an indicator, and titrates the resulting solution with the sodium hydroxide solution to the phenolphthalein endpoint. The difference between the final and initial buret... 

The concentration of a certain sodium hydroxide solution was determined by using the solution to titrate a sample of potassium hydrogen phthalate (abbreviated as KHP). KHP is an acid with one acidic hydrogen and a molar mass of 204.22 g/mol. In the... 

The pH titration curves for the determination of the equilibrium constants in HjO were recorded with a Metrohm E536 potentiograph connected to a Metro-hm E665 dosimat and a Metrohm 6.0222.100 combined macro glass electrode. The pH calibration of the instrument was done with the mentioned buffer solutions at pH 4.00, 7.00 and 9.00. The titer of the NaOH used was determined with potassium hydrogen phthalate. 

Using ammonium pyrrolidine dithiocarbamate/methyl isobutyl ketone, hexa-valent chromium is extracted from a solution containing potassium hydrogen phthalate and determined by atomic absorption. 

Potassium hydrogen phthalate, often abbreviated KHP, can be obtained in high purity and is used to determine... 

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