The rate of a reaction is the speed at which products form or reactants disappear

speed at which product is formed

Explanation:

The rate of a reaction is defined as the speed at which product is formed. The primary aim of  a chemical reaction is to obtain a product and hence it's rate of formation is usually expressed as product per unit time.

A further proof for this is in the knowledge of factors that affect the rate of chemical reaction. These factors are generally used industrially to increase the rate of chemical reaction. For example, addition of catalyst.

Addition of catalyst is used to increase the rate of chemical reaction by reducing the reaction's activation energy. Activation energy is the minimum amount of energy that must be overcome for a reaction to occur. Catalyst is thus added to get more products in the shortest possible time by reducing the activation energy of the reaction. From this illustration, we can see that the rate of reaction is increased in order to make more products and NOT for reactants to disappear.

Answer : The correct option is, The products will be different than the reactants.

Explanation :

Chemical reaction : During a chemical reaction, two or more reactants are converted to the one or more different products. Or we can sat that a chemical reaction rearrange the component of atoms of reactants to form a different products.

For example : Magnesium react with water to give magnesium hydroxide and hydrogen gas.

The reaction will be,

Hence, the correct option is, The products will be different than the reactants.