Question

A mysterious white powder is found at a crime scene. A simple chemical analysis concludes that the powder is a mixture of sugar and morphine (C17H19NO3), a weak base similar to ammonia. The crime lab takes 10.00 mg of the mysterious white powder, dissolves it in 100.00 mL water, and titrates it to the equivalence point with 2.84 mL of a standard 0.0100 M HCl solution. What is the percentage of morphine in the white powder?
a. 8.10%
b. 17.3%
c. 32.6%
d. 49.7%
e. 81.0%

Answer 1

Answer:

e. 81.0%

Explanation:

Morphine has Molar mass = 285.34 g/mol

Also, number of males of Morphine = Number of moles of HCl

(At equivalence point )

Now, number of moles of HCl = Molarity × volume

=0.01 mol × 2.84×10^(-3) L

= 2.84×10^(-5) mol

therefore number of moles of morphine= 2.85×10^(-5)

Mass of Morphine= No. of moles × molar mass

= 2.84×10^(-5)×285.34 g/mol

= 0.0081 g

= 8.1 mg

therefore

percentage of morphine = mass of morphine/ mass of powder×100%

= 8.1/10×100% = 81.0%

hence option e is correct.