A student added quick lime to the beaker containing water. Which of the following  is not correct observation of the student

 

Quicklime is chemically Calcium Oxide. When water is added to Quick lime, calcium hydroxide is formed and a lot amount of heat is released in this process. A hissing sound is also observed, the chemical reaction is

$\underset{\mathrm{quick} \mathrm{lime}}{\mathrm{CaO}}+{\mathrm{H}}_2\mathrm{O}\to \underset{\mathrm{slaked} \mathrm{lime}}{\mathrm{Ca}{\left(\mathrm{OH}\right)}_2}+\mathrm{Heat}$