Chemists use activity series to determine whether which type of reaction will occur?
combustion
double replacement
decomposition
single replacement

Chemists use activity series to determine whether A SINGLE REPLACEMENT reaction will occur.

Activity series refers to a series of metals that are arranged in order of reactivity starting from the highest to the lowest. The series is used essentially to determine the products that are formed from single displacement reactions. A metal that is higher in the activity series will always replace a metal that is lower in the series if rhe two of them exist in the same solution. This is because, a metal that is higher in the series will be more reactive than a metal that is below in activity series.