When metals react with acids, a salt of the metal and hydrogen gas are formed. We can investigate the reactivity of different metals by placing samples in acid and comparing the results.

FOLLOWING the work of Bowden, Gregory and Tabor 1, we have made friction-temperature measurements on mono- and multi-layers of calcium stearate and stearic acid on various metals. These authors ...

The film further illustrates nitric acid's behavior with indicators and active metals, highlighting reactions that produce hydrogen gas and various nitrogen oxides.