For the following unbalanced equation, what type of reaction is NH_(3)arrow N_(2)+H_(2) combustion decomposition double replacement single replacement synthesis

The given chemical equation is $NH_{3}\rightarrow N_{2}+H_{2}$. In this reaction, a single compound (NH3) breaks down into two simpler substances (N2 and H2). This is characteristic of a decomposition reaction. Therefore, the correct answer is B, decomposition.