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Synthesis Reaction Definition

In chemistry, synthesis refers to how complex chemical entities or compounds are formed from smaller and simpler units. Generally, synthesis reactions can be demonstrated, such as

A + B → C

Here A and B are some smaller groups that bind together to form a larger compound. That's why synthesis chemical reaction are called combination reactions as well.

To simplify synthesis reactions, we divide them into three main types such as

  1. Synthesis chemistry by element in which two elements react to form a new compound such as

    C + O2 → CO2
  2. Synthesis by compounds where two simple compounds react together to form a larger one such as

    2CaO + 2H2O → 2Ca(OH)2
  3. Synthesis in which one element and one compound react to form a new compound such as

    2CO + O2 → 2CO2

Related: Complete demonstration of metal displacement reaction in an aqueous medium.

Besides the nature of reactants, synthesis reactions can also be divided based on the number of products.

The reactions in which only one product is formed are known as simple synthesis or direct combination reactions. All the examples mentioned above represent single synthesis chemical reactions.

Another very common example of a simple synthesis reaction is the rust formation which occurs as follows

4Fe + 3O2 → 2Fe2O3

On the other hand, the chemical reactions in which two or more products are formed are called complex synthesis reactions.

The most common example of a complex synthesis reaction is the formation of glucose by photosynthesis. The reaction occurs as follows

CO2 + H2O → C6H12O6 + O2

Related: Sodium react with chlorine to form sodium chloride NaCl. Learn more about the reaction of sodium and chlorine and what happens when they react with each other.

Importance of synthesis in chemistry

The synthesis reactions are used greatly for the manufacturing of substances required for daily life.

Besides synthesizing essential products, the chemists also synthesize naturally-existing compounds in the lab to understand their nature and structure.

Similarly, synthesis allows chemists to form chemical compounds that don't exist in nature to elevate the living standards and for research purposes.

The main goal of synthesis is to produce final products in larger quantities in a shorter time. Moreover, almost all kinds of chemical compounds undergo synthesis reactions.

However, organic compounds possess the highest potential to perform complex compounds by synthesis reactions. Click on to learn about balancing complex chemical equations.

Process of synthesis

As we know, chemical compounds are formed by the combination of multiple atoms of different elements.

These elements are joined with each other by chemical bonds in a compound. During the chemical synthesis, the existing bonds are broken down, and new bonds are formed.

We can't say that a complex chemical compound can form just in a single-step reaction.

Instead, forming a complicated chemical compound involves a series of individual reactions, which begins from the decomposition of reactants and ends with forming the desired product.

In each step, usually, a single bond is formed or broken down on either side.

Synthesis Reaction Example:

An example of a complex synthesis reaction is as follows

(CH3)3CCl + OH- → (CH3)3COH + Cl-

It is an overall reaction where two complicated compounds are reacting together to form different end products. The mechanism for this reaction comprises of two steps such as

(CH3)3CCl → (CH3)3C + Cl-
(CH3)3C + OH- → (CH3)3COH

Related: Complete guide for balancing redox reaction in basic solution.

Planning the pathway of a synthesis reaction

As stated before, the synthesis of a complex chemical compound comprises multiple steps. That's why predicting the right procedure or the exact mechanism is quite difficult.

To sort out this confusion, the chemists plan the entire synthesis route by visualizing the final product.

From the end product, the chemists predict the path in a backward direction - moving from the end product towards the starting materials.

During the formation of lab-generated compounds, the synthesis routes are formulated based on the availability and cost of starting materials, the power required to proceed further, and the price for purifying the final product.

Chemists also get help from their knowledge of the nature of functional groups to determine the highly favored and beneficial pathway.

Things that should be considered while planning the pathway of synthesis

  • Go with the reaction route, which alters only one part of the compound at one time. It reduces the formation of multiple intermediates.
  • Since many reactions are occurring side by side during the synthesis reaction, they can compete. Resultantly, many side products can be formed, which lowers the yields of the desired product. Thus, go with the reaction route, which yields the product in large amounts.
  • Formation of side products can be useful and problematic depending upon the nature of the by-product. A side product is only useful if it is commercially valuable. On the other hand, if it is of no value and adds to the cost of separation and purification, try to change the route to suppress its formation.

Final words

The rules of balancing chemical equations for synthesis reactions are just the same as for other chemical reactions.

Synthesis reactions are one of those chemical reactions which are greatly used in the labs for the production of highly essential products. These reactions are very useful for equation balancing process.

Either the synthesis reactions occur naturally, or within a lab-controlled environment, its products are always formed in larger quantities.

Also find what are endothermic reactions and exothermic reactions and what is general chemical equation for such reactions.