The “free-base” form of cocaine (C₁₇H₂₁NO₄) and its protonated hydrochloride form (C₁₇H₂₂ClNO₄) are shown below; the free-base form can be converted to the hydrochloride form with one equivalent of HCl. For clarity, not all the carbon and hydrogen atoms are shown; each vertex represents a carbon atom with the appropriate number of hydrogen atoms so that each carbon makes four bonds to other atoms.
(a) One of these forms of cocaine is relatively water-soluble: which form, the free base or the hydrochloride?

(b) One of these forms of cocaine is relatively insoluble in water: which form, the free base or the hydrochloride?

(c) The free-base form of cocaine has a solubility of 1.00 g in 6.70 mL ethanol (CH₃CH₂OH). Calculate the molarity of a saturated solution of the free-base form of cocaine in ethanol.

(d) The hydrochloride form of cocaine has a solubility of 1.00 g in 0.400 mL water. Calculate the molarity of a saturated solution of the hydrochloride form of cocaine in water.

(e) How many mL of a concentrated 18.0 M HCl aqueous solution would it take to convert 1.00 kilograms (a “kilo”) of the free-base form of cocaine into its hydrochloride form?

Transcribed Image Text:

H3C-N- CH3 Cocaine (Free base) + HCI H CH H₂C-N+ CH3 Cocaine hydrochloride