Referring to Table 16.1, specify which indicator or indicators you would use for

Question

Referring to Table 16.1, specify which indicator or indicators you would use for the following titrations. (Select all that apply.)

thymol bluebromophenol bluemethyl orangemethyl redchlorophenol bluebromothymol bluecresol redphenolphthalein

thymol bluebromophenol bluemethyl orangemethyl redchlorophenol bluebromothymol bluecresol redphenolphthalein

(a) HCOOH versus NaOH

thymol bluebromophenol bluemethyl orangemethyl redchlorophenol bluebromothymol bluecresol redphenolphthalein

(b) HCl versus KOH

thymol bluebromophenol bluemethyl orangemethyl redchlorophenol bluebromothymol bluecresol redphenolphthalein

(c) HNO3 versus CH3NH2thymol bluebromophenol bluemethyl orangemethyl redchlorophenol bluebromothymol bluecresol redphenolphthalein

Explanation / Answer

he indicators to choose from:
thymol blue (pH range 1.2-2.8)
bromophenol blue (3.0 - 4.6)
methyl orange (3.1 - 4.4)
methyl red (4.2 - 6.3)
chlorophenol blue (4.8 - 6.4)
bromothymol blue (6.0 - 7.6)
cresol red (7.2 - 8.8)
phenolphthalein (8.3 - 10)

so,

A) HCOOH is a weak acid (Ka = 1.8 x 10-4) and NaOH is a strong base. The pH at the equivalence point should be around 10 or 11. use phenolphthalein

b) HCl is a strong acid and KOH is a strong base. The pH at the equivalence point should be 7. use bromothymol blue.

c) HNO3 is a strong acid and CH3NH2 (Kb = 4.4 x 10-4) is a weak base. The pH at the equivalence point should be around 3 or 4. use methyl orange or bromophenol blue.

Related Questions

Navigate

• Browse (All)
• Browse R
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.