A pH indicator was found to have a pKa = 5.00. At a pH of 7.00, which one of the following should be observed and why?
Select one:
a. The color of the solution will be the color of In- because [HIn] > [In-] at this pH.
b. The color of the solution will be the color of HIn because [In-] > [HIn] at this pH.
c. The color of the solution will be the color of In- because [In-] > [HIn] at this pH.
d. The color of the solution will be the color of Hin because [HIn] > [In-] at this pH.
1. The pH of a 50.0 mL solution of 0.500 M HSCN (the analyte) was measured and found to be 3.80. What is pKa for the acid based on this measurement? 2. Trace amounts of an Indicator HIn was added to the solution described above. The indicator has a pKa (pkIn) of 11.85. This indicator is known to be yellow in solution in the form HIn and blue in solution in the form In- . In a forward titration, a...
Suppose you have an indicator that turns from yellow to red over a pH range of 6.4 to 8.0, respectively. Fill in the blanks for each of the following. What color is the acidic form of the indicator? What is the pKa of the indicator? What color is the indicator when pH = pKa?
Universal indicator is a solution which contains several acid base indicators and provided sufficient color changes to estimate pH over a wide range. One such indicator contains a mixture of thymol blue, phenolphthalein, and methl orange. Determine the color of this indicator at a) pH=1.5, b) pH=4, c) pH 6.5, d) pH=9, and e) pH=11.5. Explain reasoning.
a) An unknown indicator (called “HIn”) has a Ka of 4.0 x 10-6. The color of the neutral form is green, and that of ionized form is red. The indicator is added to a HCl solution, which is then titrated against a NaOH solution. At what pH will the indicator change color? b) 350. mL of a NaOH solution was added to 500. mL of 2.50 M HNO2. The pH of the mixed solution was 1.75 units greater than that...
Which of the following acids, whose pKa values are given next to them, would have the strongest conjugate base? pKa a) H2SO4 b) CH3COOH 4.8 c) HS 12.9 d) NH* 2.0 9.2 Reaction of a carboxylic acid with an alcohol produces: a) an alkane b) an ester c) a ketone d) an amide During the neutralisation of a weak acid by a strong base the pH of the solution equals the pKa of the acid: a) at the beginning of...
The pOH of an aqueous solution at 25°C was found to be 7.00. The pH of this solution is The hydronium ion concentration is The hydroxide ion concentration is M .
When 1.00 L of 0.45 M acetic acid (pKa = 4.74) is mixed with the exact volume of 0.55 M NaOH required to convert the acid to its conjugate base, at the endpoint the solution will have a: A. pH < pKa B. pH > 7.00 C. pH = pKa D. pH = 7.00 E. pH < 7.00
3) a) What is the pKb for a weak base if the pH of a 0.125M solution of this weak base was found to be 8.16? 4) When a weak acid is added to water to make a 0.250M solution, the acid was found to be 1.5% ionized. What is the Ka and pKa of this weak acid? 5) At 60°C, Kw = 9.6x10-14 (Kw increases as the temperature increases). a) For pure water at 60°C, what is the [H+] and pH....
Table 2: Indicator, pH Range, and Color Change Beaker Indicator Amount Needed for Reaction to Complete pH Range pH at Color Change Color (Initial:Final) 1 Bromothymol Blue 6 6.0-7.5 6.6 Blue > Light Yellow 2 Turmeric Indicator 6 7.5-8.8 5.3 Light Red > Yellow 3 Methyl Orange 20 2.3-4.6 7.9 Orange > Pink Table 3: Titration Data Part 2: mL Citric Acid Added Part 2: pH Part 3: mL Citric Acid Added Part 3: pH Part 3: Color 0.0 10.5...
Calculate the pH of the following aqueous solution: 0.17MHOCl (pKa= 7.46) Select one: a. 9.89 b. 4.11 c. 5.77 d. 8.23