The last section of the syllabus asks you to consider an industrial process and the different factors that are important such as availability of materials, environmental impact, yield, rate etc.
So what your teacher is likely doing is using the Solvay process as a case study/example of those above things. Although technically solvay was in the old syllabus i guess you can still use it as the example for that syllabus area, but commonly people would do Haber process because there’s less steps and easier to memorise