litmus

n. a purple dye from plants that turns red in acid and blue in alkaline liquids.

n. a water-soluble mixture of different dyes extracted from lichens, used as a pH indicator.

“The scientist extracted litmus from the lichen to create a new batch of testing solution.”

“Litmus is primarily used to determine acidity or alkalinity, as its constituent chromophores undergo structural changes in response to protonation.”

Technical

n. a quick test using special paper to see if a liquid is an acid.

n. a chemical test for acidity or alkalinity, typically performed using paper strips treated with the dye.

“We used a strip of litmus to check the pH level of the swimming pool water.”

“The chemistry students performed a litmus test on various household liquids to observe the immediate color transition from blue to red.”

n. a simple way to judge someone's character or the success of a plan.

n. a figurative indicator or test that relies on a single factor to provide a decisive evaluation of a situation or person.

“The way a person treats a waiter is often a litmus test for their true character.”

“The candidate's stance on environmental regulation served as a litmus test for the party's more progressive wing during the primary elections.”

Academic