鈉與水反應爆炸的根本原因？

主要原因有二：

鈉和水反應大量放熱並放出氫氣，當鈉熔體內部聚集了過多的熱，會爆炸，並可能點燃上方的氫氣。

上面的，是高中教材會講的。

鈉單質內原子高度緊密，鈉原子失去電子又過快，導致反應中的每一個瞬間鈉單質內部都存在著大量高度密集的鈉正離子，強烈的電勢能會轉化為動能，這個過程叫庫倫爆炸。

評論區要求解釋一下這個過程，那我簡單說一下：

鈉原子失去電子速率過快，確切的說是近乎瞬間，每1皮秒釋放一個電子。這個速率快於電子還原水電離出的氫離子產生氫氣的過程，因此會有過量的電子積累產生溶劑化電子，即水合電子；

與此同時，鈉原子簇之間距離非常近，他們失去電子會變成鈉離子，距離極近的鈉離子之間的排斥由於鹼金屬液滴太小無法束縛液滴內部電荷而發生爆炸。

庫倫爆炸的硬定義是：從強電磁場耦合電子激發能到原子運動的一種現象。有著相同電荷的粒子的庫倫斥力可以斷裂維持固體的鍵。

Abstract：

Alkali metals can react explosively with water and it is textbook knowledge that this vigorous behaviour results from heat release, steam formation and ignition of the hydrogen gas that is produced. Here we suggest that the initial process enabling the alkali metal explosion in water is, however, of a completely different nature. High-speed camera imaging of liquid drops of a sodium/potassium alloy in water reveals submillisecond formation of metal spikes that protrude from the surface of the drop. Molecular dynamics simulations demonstrate that on immersion in water there is an almost immediate release of electrons from the metal surface. The system thus quickly reaches the Rayleigh instability limit, which leads to a 『coulomb explosion』 of the alkali metal drop. Consequently, a new metal surface in contact with water is formed, which explains why the reaction does not become self-quenched by its products, but can rather lead to explosive behaviour.

謝謝評論幫我這個懶人找到了這篇文章

Coulomb explosion during the early stages of the reaction of alkali metals with water