Question

Correct and balance the following equation
$Ca + {H_2}O \to CaOH + H$

Answer 1

Hint: A chemical equation is a symbolic representation of a chemical reaction in which the reactants and products are represented by their respective chemical formulae. The reactant side is said to be the part of the chemical equation to the left of the ‘$ \to $’ symbol while the product side is the part to the right of the arrow symbol.

Complete answer:
When an active metal reacts with water, an oxide or hydroxide is formed, as well as hydrogen gas. Metals that react strongly or quickly with other chemicals are referred to as active metals. Water is known to react with the highly active metals.
$Ca(s) + 2{H_2}O(l) \to Ca{(OH)_2}(aq) + {H_2}(g)$

Reactant side	Product side
$Ca = 1$	$Ca = 1$
$H = 4$	$H = 2 + 2 = 4$
$O = 2$	$O = 2$

Hence, the above reaction is correct and balanced. Calcium is oxidised because it has an oxidation number of $0$, whereas $C{a^{2 + }}$ in $Ca{(OH)_2}$ has an oxidation number of $ + 2$. Because the oxidation number of hydrogen changes from $ + 1$ to $0$, it is reduced.

Additional Information: The chemical formula $Ca{(OH)_2}$ is used to describe calcium hydroxide, often known as slaked lime. In its solid state, it is an inorganic compound with a white, powdery appearance. In its crystalline form, however, $Ca{(OH)_2}$ appears colourless. This compound is also known as hydrated lime, slack lime, pickling lime, and caustic lime.

Note:
 In a balanced chemical equation, the total number of atoms of an element present in a species equals the product of the stoichiometric coefficient and the number of atoms of the element in one molecule of the species. Stoichiometric coefficients are assigned in a way that balances the total number of atoms of an element on the reactant and product sides when balancing chemical equations.