1. With dilute nitric acid:
The primary reaction is the formation of hydrogen sulfide gas (H₂S) and sodium nitrate (NaNO₃):
2Na₂S(aq) + 2HNO₃(aq) → 2NaNO₃(aq) + H₂S(g)
* Hydrogen sulfide (H₂S): This is a colorless gas with a strong, foul odor (like rotten eggs). It is toxic and flammable.
* Sodium nitrate (NaNO₃): This is a white solid that is soluble in water.
2. With concentrated nitric acid:
If concentrated nitric acid is used, the reaction becomes more complex and can produce additional products, including:
* Sulfur (S): A yellow solid.
* Nitrogen oxides (NOₓ): These are gases that can be toxic.
* Water (H₂O):
Important Considerations:
* Safety: The reaction produces toxic and flammable gases. It should be performed in a well-ventilated area and with appropriate safety precautions.
* Temperature: The reaction is exothermic, meaning it releases heat. It's essential to control the temperature to prevent runaway reactions.
* Concentration: The concentration of the nitric acid significantly affects the products formed.
In summary:
Dilute nitric acid reacts with sodium sulfide to produce hydrogen sulfide gas and sodium nitrate. Concentrated nitric acid can lead to the formation of additional products, including sulfur and nitrogen oxides. Always use proper safety precautions when working with these chemicals.
