1.水在直流电的作用下分解(研究水的组成实验)
$2H_ {2}O \stackrel {通电} {=} 2H_ {2} $↑$+ O_ {2} $↑
3.二氧化碳可溶于水
$CO_ {2} + H _ {2}O \stackrel {} {=} H_ {2}CO_ {3} $
2.生石灰溶于水
$CaO + H _ {2}O \stackrel {} {=} Ca(OH)_ {2} $