Question

Write two observations you make when quicklime is added to water.

Answer 1

Quicklime is Calcium oxide$\left(\mathrm{CaO}\right)$.

When Quicklime is added to water, the following changes are observed:

1. Heat is evolved- which indicates that this is an exothermic reaction.
2. Slaked lime (Calcium hydroxide) is produced as a product- which is used for whitewashing.

The reaction can be written as:

$$\begin{gathered} \mathrm{CaO}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to \mathrm{Ca}{\left(\mathrm{OH}\right)}_2\left(\mathrm{s}\right)+∆ \\ (\mathrm{Calcium}\mathrm{oxide})\left(\mathrm{water}\right)(\mathrm{Calcium}\mathrm{hydroxide}) \end{gathered}$$