Question

question 21
sodium ions and calcium ions are examples of
a cations.
b unchargedparticles.
c anions.
d salts.

question 22
lipids
a are insoluble in water.
b include phospholipids, cholesterol, and fats.
c contain c, h, and o, but with proportionately less oxygen than in carbohydrates.
d all of theabove.
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Explanation:

Question 21

• Option A: Cations are positively charged ions. Sodium ions ($\text{Na}^+$) and calcium ions ($\text{Ca}^{2+}$) have positive charges, so they are cations.
• Option B: Sodium and calcium ions are charged, so this is incorrect.
• Option C: Anions are negatively charged ions, while sodium and calcium ions are positive, so this is incorrect.
• Option D: Salts are compounds formed from cations and anions, not the ions themselves, so this is incorrect.

• Option A: Lipids are non - polar molecules, and water is polar, so lipids are insoluble in water.
• Option B: The main types of lipids include phospholipids, cholesterol, and fats (triglycerides).
• Option C: Lipids are composed of carbon, hydrogen, and oxygen, and they have a lower proportion of oxygen compared to carbohydrates.
• Since options A, B, and C are all correct descriptions of lipids, option D (all of the above) is the right choice.

Answer:

A. cations.

Question 22