Which of the following is not a mixture? a. antibiotic b. evaporated milk c. brewed coffee d. hydrogen chloride 4. Which of these is a homogeneous mixture? a. air b. blood c. clouds d. smog
The correct answer and explanation is:
Correct Answers:
- Which of the following is not a mixture?
Answer: d. hydrogen chloride - Which of these is a homogeneous mixture?
Answer: a. air
Explanation (Approximately 300 Words)
Question 1: Which is not a mixture?
A mixture is a combination of two or more substances that are physically combined and can be separated by physical means. In mixtures, the substances retain their individual properties.
- a. Antibiotic – Most antibiotics, especially in pill or liquid form, are actually mixtures containing the active compound along with fillers, preservatives, or solvents.
- b. Evaporated milk – This is a mixture, primarily composed of water, fats, sugars, and proteins.
- c. Brewed coffee – Coffee is a mixture of water and hundreds of soluble compounds extracted from coffee grounds.
- d. Hydrogen chloride (HCl) – This is a pure substance, not a mixture. It is a compound, formed by chemically combining hydrogen and chlorine in a fixed 1:1 ratio. Unlike a mixture, the components of a compound cannot be separated by physical means.
Therefore, hydrogen chloride is not a mixture; it is a compound.
Question 2: Which is a homogeneous mixture?
A homogeneous mixture is a mixture with a uniform composition throughout. Its components are not visibly distinguishable.
- a. Air – Air is a homogeneous mixture of gases like nitrogen, oxygen, carbon dioxide, etc. The gases are evenly mixed, and you can’t distinguish one gas from another with the naked eye.
- b. Blood – Blood is a heterogeneous mixture. It contains visible components under a microscope like red and white blood cells suspended in plasma.
- c. Clouds – Clouds are made of tiny water droplets or ice crystals suspended in the air, making them heterogeneous.
- d. Smog – Smog is a heterogeneous mixture of pollutants, gases, and particulates.
Hence, air is the correct answer because it is uniform and homogeneous throughout.