This site provides an explanation about the mechanism of the explosion.
...causes an explosion because the metal dissolves, generating an
extreme amount of heat and transferring electrons to the water. The
dissolution step also generates steam and forms hydroxide ions and
hydrogen, which can be ignited, making the process even more
Some researchers have puzzled over how the process can occur so
quickly, though. They recognized that the steam and hydrogen generated
early on in the reaction should form a buffer layer over the metal
surface and impede water from continuing to react.
...within a fraction of a millisecond of making contact with water,
the Na/K droplets form numerous spikes that protrude into the water.
Molecular dynamics analysis indicated that nearly instantaneous
transfer of electrons from the spikes to the water rapidly generates
positively charged alkali ions, which vigorously repel and cause a
so-called Coulomb explosion. It is the speedy manner in which that
process propagates and generates reactive metal surfaces that triggers
the overall explosion.
The researchers have figured out many of the key aspects that enable
this highly exothermic reaction to become explosive, rather than
It does not generally reacts with any other liquids. Hence they are stored in mineral oil.
It is highly reactive with water and is stored usually under hexane or
other hydrocarbons, or under an inert gas (usually dry nitrogen or
argon) if high purity and low levels of oxidation are