How to find out if two compounds will react or not in chemistry?

React both the elements(its element not compound) with a common compound. if there is any change in any color , smell , or taste or any type of evolution of gasthen we can sense the reaction taking place.

1= c 2= a or d3 = idk sorry 4= c5= c

Answerd. may include all of these are many definitions of bases: the  brønsted-lowry definition of acids and bases says that bases are proton acceptors.the arrhenius definition of acids and bases says that bases increase [oh⁻] in solution (thereby producing oh⁻ ions)the lewis definition of acids and bases says that bases donate electron pairs.therefore, the sensible answer is that a base may include all of the described characteristics.