What information are provided by the chemical equation: $2\mathrm{Mg}+{\mathrm{O}}_2\to 2\mathrm{MgO}$

An equation that lists the components of a chemical reaction is known as a chemical equation. Reactants are the compounds that interact with one another. When the reactants combine, new chemicals called products are created.

A studied chemical equation must constantly be in equilibrium. An equation's two sides must include an equal number of each element's atoms for a chemical reaction to be considered balanced. The rule of conservation of mass must always be followed in a chemical equation in order to be considered balanced.

The law of conservation of mass states that because matter cannot be generated or destroyed and cannot transform into a different element during a chemical reaction, the quantity of each element must remain constant. For instance, the quantity of any given element in the reactants will always be the same as the quantity of that element in the resulting products.

The chemical equation in the question $2\mathrm{Mg}+{\mathrm{O}}_2\to 2\mathrm{MgO}$ gives us the information that two atoms of magnesium in reaction with one molecule of dioxygen form two molecules of magnesium hydroxide.

Hence option (A) is correct.