After dissolving the KHP with water, a student noticed some undissolved solid, b

Question

After dissolving the KHP with water, a student noticed some undissolved solid, but continued with the titration as instructed by the procedure. He titrated until the pink color persisted for 30 sec and recorded the volume of titrant required. Preparing for the second determination, he set the reaction solution aside and added some more NaOH to the buret. He was about to pour the reaction solution down the drain, so he could rinse and reuse the flask, when he saw that the pink color had disappeared! A) What happened? B) what can the student do to correct for this errand salvage this trial? How should the dat sheet be modified to reflect the correction?

Explanation / Answer

A)The undissolved KHP dissolved and it resulted in the decoloration of the phenolphthalein.  

B). Before starting the titration, solids should be dissolved completely. Or liquids should be mixed properly.

C). The volume of NaOH used is less than the corresponding equivalent to the moles of KHP. This will result in reporting the wrong concentration of the unknown.

if KHP is unknown, the reporting concentration will be lower than the actual concentration.

if NaOH is the unknown, the reporting concentration will be higher than tha actual concentration.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

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