Question

How do you identify the reactants and products in the following reaction:
$potassium{\text{ }} + {\text{ }}water \to potassium{\text{ }}hydroxide + hydrogen?$

Answer 1

In general a chemical reaction is expressed with the help of reaction arrows in one direction or in both directions. One directional arrow is one way reactions and two directional arrows are two way reactions.

Complete step by step answer:
A chemical reaction is the combination of two or more substances to produce new substances which are different from the initial ones. The substances which are used to mix or combine are known as substrates or reactants. The substances which we get after the reaction are called products.
In order to express a chemical reaction on paper we use different types of arrows. Some of them which are used regularly include ’$\to$ ‘, ‘$\leftarrow$’ , ‘$\rightleftharpoons$’, ‘’ etc. The single arrows are pointed towards a single direction but the double arrows are pointed towards one direction. The substances which are present on the side of the pointed arrows are called as products and the substances which are present on the other side are assigned as reactants.
Thus the given reaction is
$potassium{\text{ }} + {\text{ }}water \to potassium{\text{ }}hydroxide + hydrogen$
The arrow is pointed towards two substances potassium hydroxide and hydrogen. So the products of the reaction are potassium hydroxide and water. And the reactants of the reaction are potassium and water.
Usually a chemical equation is written as the reactants are on the left side of the arrow and the products on the right side of the arrow. This represents that the reactants react to give products.

Note:
In case of double arrows however the reaction occurs simultaneous in both directions after a period of time. So initially the reactants combine to give products. After some time the reverse reaction starts and the products now become reactants and combine to give back products which are initial reactants.