Phenolphthalein is a weak acid, explain what it means to be a weak acid and look up phenolpthalein’s pKa.
A weak acid is an acid that partially dissociates into its ions in an aqueous solution or water.
pKa of phenolphthalein -> 9.4
Phenolphthalein is a weak acid, explain what it means to be a weak acid and look...
Define an acid-base indicator. Explain why phenolphthalein is chosen as an indicator for the titration for standardizing NaOH, determining % composition of KHP, and determining the acid content of vinegar. (Look up for the Ka for the indicator online and explain why this indicator is chosen for these titrations)
Which of the following color indicators would be most appropriate for the titration of a weak base with a strong acid. A. Phenol red, pKa =8.0 B. Phenolphthalein, pKa =9.5 C. Bromophenol blue, pKa =4.3 D. Alzarin yellow, pKa = 11.2
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24 Phenolphthalein is a commonly used indicator that is colorless in the acidic form (pH less than 8 3) and pink in the base form (pH greater than 100) It is a weak acid with a pka of 8.7. What fraction is in the acid form when the ocid color is apparent? What fraction is in the base form when the base color is apparent?
24 Phenolphthalein is a commonly used indicator that is...
Explain how the titration of a weak acid by addition of a strong base could be used to determine the pKa value of the weak acid.
Explain why cyclohexylaminoethanesulfonic acid (pKa = 9.39) is a good weak acid to act as a buffer for a capillary electrophoresis experiment which must have a pH of 9.50.
Consider the structures of KHP and phenolphthalein and explain why each has a single acidic hydrogen (one that dissociates as a weak acid) when there are several hydrogen atoms in the structure (HINT: Review the rules for predicting acid strength).
find the term isosbestic point.? [a. Explain why the isobestic point would be a poor choice of wavelength for determiningpKa? 5. Phenolphthalein is an indicator often used for weak acid-strong base titrations. The acid form of phenolphthalein is colorless and the base form is pink. Do you think the pKa of phenolphthalein would be determined using the same the method from this experiment to find the pKa for bromothymol blue? Explain why or why not? I dont need the answer...
Phenolphthalein is used in titrating KHP with NaOH. Why? Is phenolphthalein required for a potentiometric titration of a weak acid with NaOH? Why or why not?
Out of the following acids below that are weak acids, look up the Ka values online. If more than one reactions can occur when the species is placed in water, write out each reaction and assign a Ka to each reaction. Calculate the pKa for each weak acid. 0.5 M HCL 0.5 M HCOOH 0.5 M CH3COOH 0.5 M H2SO4 0.5 M H3PO4 After, calculate the theoretical pH for 0.5 M of each of these acids.
In a weak acid when [HA]=[A-]the pH = the pKa. What is the pH after adding 0.50 moles HCl to a solution of HA =1 mole and A- = 1 mole. The pKa of the weak acid = 4