Nitric acid:
Materials:
1. Sodium nitrate or
Potassium nitrate (salt petre)
2. Distilled water
3. concentrated sulfuric acid
Equipment:
Directions:
Pour 32 milliliters of concentrated sulfuric acid into the retort.
Carefully weigh out 68 grams of potassium nitrate. Add this to the acid slowly. If it all does not dissolve, carefully stir the solution with the glass rod until it does.
Place the open end of the retort into the collecting flask, and place the collecting flask in the ice bath.
Begin heating the retort, using low heat, continue heating until liquid begins to come out of the end of the retort. The liquid that forms is nitric acid. Heat until the precipitate in the bottom of the retort is almost dry,
Or until no more nitric acid is forming. CAUTION: if the acid is headed too strongly, the nitric acid will decompose as soon as it is formed. This can result in the production of highly flammable and toxic gasses that may explode. It is a good idea to set the above apparatus up, and then get away from it.
Potassium nitrate could also be obtained from store bought black powder, simply by dissolving black powder in boiling water and filtering out the sulfur and charcoal. To obtain 68 grams of potassium nitrate, it would be necessary to dissolve about 90 grams of black powder in about one liter of boiling water. Filter the dissolved solution through filter paper in a funnel into a jar until the liquid that pours through is clear. The charcoal and sulfur in black powder are insoluble in water, and so when the solution of the water is allowed to evaporate, potassium nitrate will be left in the jar.