3/26/2017 05:00 PM A 5.4/10 3/26/2017 02:17 AM Gradebook Print Calculator Period

Question

3/26/2017 05:00 PM A 5.4/10 3/26/2017 02:17 AM Gradebook Print Calculator Periodic Table Question 8 of 9 Map Sapling Learning The flask shown here contains 0.845 g of acid and a few drops of phenolphthalein indicator dissolved in water. The buret contains 0.170 M NaOH. mL What volume of base is needed to reach the end 20 point of the titration? 25 30 Number 35 mL base 40 45 What is the molar mass of the acid (assuming it is diprotic and that the end point corresponds to the second equivalence point? V Add base to the solution until it just turns pink. You may need to reset the titration if Number you go past the end point. g mol O Previous ® Give Up & View Solution Check Answer Next HExit Hint

Explanation / Answer

I think this question relates to the KHP/NaOH standardization problem.

1) Molar mass of KHP = 204.22 g/mol

Moles of KHP = (0.845 g)/(204.22 g/mol) = 4.138*10-3 mole.

The neutralization reaction is

KHP + NaOH ------> NaKP + H2O

At the equivalence point, moles of NaOH neutralized = moles of KHP; therefore, moles of NaOH neutralized = 4.138*10-3 mole.

Therefore, volume of NaOH required = (4.138*10-3 mole)/(0.170 mol/L) = 0.02434 L = (0.02434 L)*(1000 mL/1 L) = 24.34 mL 24.3 mL (ans).

2) Does this question relate to the previous one? If it does, then part (1) isn’t correct and more information is needed to answer both the questions.

Related Questions

Navigate

• Browse (All)
• Browse 3
• Subjects

---

---

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