Question

$\underset{\mathrm{Potassium}\mathrm{nitrate}}{{\mathrm{KNO}}_3\left(\mathrm{s}\right)}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}\to \underset{\mathrm{Potassium}\mathrm{Hydroxide}}{\mathrm{KOH}\left(\mathrm{l}\right)}+\underset{\mathrm{Nitric}\mathrm{acid}}{{\mathrm{HNO}}_3\left(\mathrm{l}\right)}$ The above reaction is _________ reaction.

Answer 1

Endothermic reactions:

1. Endothermic processes require the utilization of external energy in order to continue. External energy in the form of heat is very common.
2. They tend to cool their surroundings because they draw heat from them.
3. These reactions are mostly non-spontaneous because they produce more energy products than reactants. The change in enthalpy for an endothermic process is always positive.

Formation of Potassium Hydroxide:

1. When solid potassium nitrate is dissolved in water, the potassium ion is attracted by a partially negative oxygen atom, while the nitrate ion is attracted by a partially positive hydrogen atom of the water molecules, resulting in the formation of potassium hydroxide.
2. It is not highly soluble in water but as we increase the temperature of water its solubility also increases in water.
3. This is due to the fact that the energy required to dissociate the potassium cations and nitrate anions from each other in solids is greater than the energy released when these ions are hydrated. Hence, it is an endothermic reaction.

Therefore, $\underset{\mathbf{Potassium}\mathbf{}\mathbf{nitrate}}{{\mathbf{KNO}}_{\mathbf{3}}\mathbf{\left(}\mathbf{s}\mathbf{\right)}}\mathbf{+}\underset{\mathbf{Water}}{{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\mathbf{\left(}\mathbf{l}\mathbf{\right)}}\mathbf{\to }\underset{\mathbf{Potassium}\mathbf{}\mathbf{Hydroxide}}{\mathbf{KOH}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}}\mathbf{}\mathbf{+}\mathbf{}\underset{\mathbf{Nitric}\mathbf{}\mathbf{acid}}{{\mathbf{HNO}}_{\mathbf{3}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}}$

Hence, The above reaction is an Endothermic reaction.