Answer: Ammonia ([tex]NH_3[/tex])
Explanation: A synthesis reaction is one in which two or more than two elements combine together to forma single product.
The atoms present in the reactants are found on the product side. According to the law of conservation of mass, the number of atoms on both sides of the arrow must be same as the total mass must be conserved.
Thus the balanced chemical equation is:
[tex]N_2+3H_2\rightarrow 2NH_3[/tex]
