Sodium nitrate is ...

Sodium nitrate is ...

• A. Soluble
• B. Insoluble
• C. Partly soluble
• D. Reacts with water

Answer: (A)

Solubility in water is the idea being tested. Sodium nitrate is an ionic compound, NaNO3, which dissolves in water by dissociating into Na+ and NO3− ions. Nitrates are known to be highly soluble in water, so the energy gained from surrounding the ions by water (hydration) easily overcomes the lattice energy of the solid, allowing it to dissolve readily. There’s no chemical reaction with water—it’s just a physical process of dissolution, so no new substances are formed. That makes soluble the best description. The other options imply it doesn’t fully dissolve or that a chemical reaction occurs, which isn’t the case here.

Solubility in water is the idea being tested. Sodium nitrate is an ionic compound, NaNO3, which dissolves in water by dissociating into Na+ and NO3− ions. Nitrates are known to be highly soluble in water, so the energy gained from surrounding the ions by water (hydration) easily overcomes the lattice energy of the solid, allowing it to dissolve readily. There’s no chemical reaction with water—it’s just a physical process of dissolution, so no new substances are formed. That makes soluble the best description. The other options imply it doesn’t fully dissolve or that a chemical reaction occurs, which isn’t the case here.