The main use of litmus is to test whether a solution is acidic or basic. Blue litmus paper turns red under acidic conditions and red litmus paper turns blue under basic or alkaline conditions, with the color change occurring over the pH range 4.5–8.3 at 25 °C (77 °F).
Answer:
The temperature and pressure below which a supercritical fluid exists.
Explanation:
Critical point is a region on the phase diagram where fluid phases (liquids and gases) have the equal density.
This is caused by increased temperature and pressure of the fluid particles in a confided container. Supercritical fluids exist in a state above critical point.
I hope this explanation was clear.