Question

What is a synthesis reaction?
(A) A reaction in which two or more substances combine to form a new compound.
(B) A reaction of an acid and a base.
(C) A reaction in which compound forms a new compound.
(D) A reaction where atoms combine to make elements.
(E) A reaction in which a compound breaks into separate elements.

Answer 1

Hint: To solve this we must know what happens in a synthesis reaction. Recall all the reactions you have learned to find out what happens in a synthesis reaction.A reaction of an acid and a base is known as the neutralization reaction. In a neutralization reaction, acid and base react to form salt and water.

Complete step by step solution: We are asked what happens in a synthesis reaction. Synthesis reaction is also known as direct combination reaction.
The word ‘synthesis’ indicates that in the reaction a product is synthesised or formed.
Synthesis reaction is a reaction in which two or more simple substances combine to form a complex product.
The reactants of a synthesis reaction can be elements or compounds but the products are always a compound.
The general form of a synthesis reaction is as follows:
$\text{A}+\text{B}\to \text{AB}$
An example of synthesis reaction is the reaction of sodium $\left(\text{Na}\right)$ and chlorine $\left(\text{Cl}\right)$ in which sodium and chlorine combine to produce sodium chloride $\left(\text{NaCl}\right)$.
Thus, we can conclude that a synthesis reaction is a reaction in which two or more substances combine to form a new compound.

Thus, the correct option is (A) a reaction in which two or more substances combine to form a new compound.

Note: The reaction opposite to synthesis reaction is a decomposition reaction. In a decomposition reaction, one complex reactant breaks down to two or more simple products.A reaction in which two or more compounds combine to form a new compound is known as combination reaction.