Q107P - Chemistry: Molecular Nature Of Matter And Change

Question

Write balanced chemical equations for the thermal decomposition of potassium nitrate (oxygen is also formed in both the cases): (a) at low temperature to the nitrite; (b) at high temperature to the metal oxide and nitrogen.

Step-by-Step Solution

Answer

The answer is

a). $2{\mathrm{KNO}}_3\to 2{\mathrm{KNO}}_2+{\mathrm{O}}_2$

b). $2{\mathrm{KNO}}_3\to {\mathrm{K}}_2\mathrm{O}+{\mathrm{N}}_2+\frac{10}{2}{\mathrm{O}}_2$

Thermal decomposition reaction

The balanced chemical equation for the reaction at low temperature is given below.

$2{\mathrm{KNO}}_3\to 2{\mathrm{KNO}}_2+{\mathrm{O}}_2$

Here the products formed are potassium nitrite and oxygen. The chemical equation is balanced by putting 2 before the potassium nitrate on the reactant side and 2 before nitrite on the product side.

Subpart (b)

The balance chemical equation for the reaction is given below.

$2{\mathrm{KNO}}_3\to {\mathrm{K}}_2\mathrm{O}+{\mathrm{N}}_2+\frac{10}{2}{\mathrm{O}}_2$

Here the products obtained are potassium oxide, nitrogen and oxygen. The chemical equation here is balanced by balancing the number of oxygen atoms on the product side with those on the reactant side.