Question

A strip of litmus paper will appear blue in ______

Answer 1

Hint:The best use of litmus is to check whether a solution is acidic or basic. The paper gives a general indication of acidity or alkalinity to the user because it correlates to the shade of red or blue color that the paper turns to. For testing the pH of a substance, we've to drip a strip of the
paper within the solution or use a dropper or a pipette for dropping a little amount of the answer over the paper.

Complete step by step answer:
Litmus paper could be a paper that has been treated with a natural water-soluble dye obtained from lichens. The resulting piece of paper, called "litmus paper", will be used as a pH indicator.
o Blue paper turns red under acidic conditions (pH below 4.5 ) while red paper turns blue
under alkaline conditions (pH above 8.3 ). Blue litmus doesn't change color under alkaline
conditions, while the red paper doesn't change color under acidic conditions.
o Neutral paper is purplish. Neutral paper turns red under acidic conditions and blue under
alkaline conditions.
So, a strip of paper will appear blue as bases turn paper blue.

Note:
Red litmus contains a weak diprotic acid. Upon exposure to a base, hydrogen ions from the acid reacts with the bottom, producing a color change to blue. Blue paper, on the opposite hand, already contains the blue conjugate base. It reacts with an acid of varying red. While the paper is also accustomed to determine whether a solution is an acid or a base, it is not good for estimating the pH value of the liquid.