When exposed to solutions under a pH of 7, it turns red because the solution is acidic. When exposed to a solution that has a higher pH of 7 or above, the solution is alkaline, and it turns litmus paper blue. If the solution is neutral,
( pH of 7 ) then the litmus paper will turn purple.
What you are looking for is ACID so the litmus paper will turn RED.
Para and ortho is actually indicating different name structure of mixture. So if structure is different then boiling/distill/melt temprature will be also different.
