A student was asked to determine the percentage of the components in a mixture o

Question

A student was asked to determine the percentage of the components in a mixture of potassium bromide,(KBr), magnesium hydroxide, (Mg(OH)2), and barium sulfate (BaSO4). The mass of the sample of the mixture used was 3.21g. She extracted the KBr from the mixture with water and filtered the insoluble Mg(OHl2 and BaSO4 from the solution, containing the KBr. After evaporating the filtrate, she dried and recovered the KBr and found that it had a mass of 1.43 g. The student then treated the insoluble residue of Mg(OH)2 and BaSO4 with 3 M HCI which dissolved the Mg(OH)2. The student then decanted the supernatant liquid containing aqueous MgCl2 from the insoluble BaSO4. After drying the solid, she recovered 0.58 g of BaSO4. She next added 3 M KOH to the aqueous solution and Mg(OH)2 precipitated. After filtering the solution and drying the precipitate, the student recovered 1.10 g of Mg(OHl2- Question: Calculate the percent KBr in the original mixture. O 34.3% o 44.5% o 18% 0 1.20%

Explanation / Answer

Ans. Given-

            Mass of original sample = 3.21 g

            Mass of KBr recovered – 1.43 g

Now,

            % KBR in original sample = (Mass of KBr / Mass of sample) x 100

                                                = (1.43 g / 3.21 g) x 100

                                                = 44.55 %

# So, correct option is- B. 44.5 %

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

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