Balance the given equation: ${\mathrm{KClO}}_3 \to \mathrm{KCl} + {\mathrm{O}}_2$

A balanced equation is one in which the number of atoms of each element is found to be the same on the reactant side and product side.

 It should always obey the law of conservation of mass and electrical neutrality is also maintained.

We can balance the number of oxygen atoms by cross-multiplying the number of oxygen atoms on the left and right-hand sides. We can balance the potassium atoms by multiplying $2$ to $\mathrm{KCl}$ in the product side.

The balanced equation is as follows:

$2{\mathrm{KClO}}_3\to 2\mathrm{KCl}+3{\mathrm{O}}_2$

Hence option C is correct.