Nitrogen air bags

Imagine the problems encountered in designing an effective automobile air bag. In 1952 John Hetrick, an efficiency expert for the air force, started thinking about such a device after he had to stop his child from hitting the dashboard while braking 

Elemental sodium would be a dangerous product (causing burns and reacting with water if it escaped from the bag), so it is combined with the potassium nitrate to produce sodium and potassium oxides, as shown in Equation (16.55)  

These oxides, as we know, are basic anhydrides and could be quite corrosive if they came in contact with the skin. To solve this problem, the silicon dioxide placed in the pellet reacts with the oxides to produce a harmless and stable alkaline silicate glass of variable composition. 

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