Given the task definition and input, reply with output. In this task, you are given a question and answer options for that question. Using this information, you have to classify each text into different topics: medicine, nursery, psychology, chemistry, pharmacology, biology.

Question: By heating in electric furnaces of silica, calcium carbide and coal, calcium silicides are obtained. One of them:
Options: <0> It has the composition CaSi2. <1> It does not react with water. <2> Does not react with sulfuric acid. <3> It is a powerful oxidizing agent. <4> Its reaction with liquid water generates calcium silicate.
chemistry