Identify one common example of a flammable solid.

Magnesium is a common example of a flammable solid due to its high reactivity, especially when finely divided or in powder form. When exposed to heat or flame, it can ignite readily, leading to vigorous combustion. Upon burning, magnesium produces a bright white light and can reach extremely high temperatures. This characteristic makes it important to handle magnesium with care in environments where ignition sources are present.

In contrast, the other materials listed do not possess the same flammable properties as magnesium. Lead is a heavy metal that is not flammable under normal conditions; it has a high melting point and does not readily catch fire. Sodium chloride, commonly known as table salt, is not flammable and is often used as a heat stabilizer in certain chemical processes. Asbestos is a mineral known for its heat resistance and is not flammable, which is why it was historically used for insulation and fireproofing. Thus, magnesium stands out as the only material among the choices that is classified as a flammable solid in appropriate conditions.