Which of the following is not a mixture?a. Antibiotic c. Brewed coffee b. Evaporated milk d. Hydrogen chloride
Which of the following is not a mixture?a. Antibiotic c. Brewed coffee b. Evaporated milk d. Hydrogen chloride
The Correct Answer and Explanation is:
Correct Answer: d. Hydrogen chloride
Explanation
A mixture is a combination of two or more substances that are not chemically bonded and can be physically separated. Mixtures can be homogeneous (uniform composition, like salt water) or heterogeneous (non-uniform, like salad).
Let’s examine each option:
- a. Antibiotic: Most antibiotics sold for treatment (like syrups or capsules) are formulated mixtures containing active pharmaceutical ingredients and excipients (binders, preservatives, coloring agents, etc.). These are mixtures because they involve more than one substance combined physically.
- b. Evaporated milk: This is milk with about 60% of the water removed, but it still contains proteins, fats, lactose, vitamins, and minerals. All these components are not chemically bonded, so evaporated milk is a homogeneous mixture.
- c. Brewed coffee: Brewed coffee is a mixture of water and various soluble compounds from ground coffee beans, like caffeine, acids, and oils. These are not chemically combined, making coffee a homogeneous mixture.
- d. Hydrogen chloride (HCl): This is not a mixture. Hydrogen chloride is a pure chemical compound, consisting of one hydrogen atom and one chlorine atom chemically bonded in a 1:1 ratio. Whether in gaseous form or dissolved in water (forming hydrochloric acid), HCl remains a compound, not a mixture. Its elements are combined through chemical bonding, and it cannot be separated by physical means like filtration or evaporation.
Thus, the only non-mixture among the options is hydrogen chloride, because it has a definite chemical composition and its components are chemically combined, distinguishing it from the physical combinations found in mixtures.
Final Answer: d. Hydrogen chloride
