5.31    describe important uses of sodium hydroxide, including the manufacture of bleach, paper and soap; and of chlorine, including sterilising water supplies and in the manufacture of bleach and hydrochloric acid.

Again, you just have to learn it!

Exam tips

·        Do not just write one word answers like “bleach”.  Remember the magic words again: “to make …”, e.g., “chlorine is used to make bleach”.

·        Don’t use the words “to purify water” or “to clean water”.  The correct terminology is “to sterilise”, “to disinfect” or “to kill bacteria in” water (for drinking or for use in swimming pools).