Acid test: blue litmus paper turns red in the presence of lemon juice (citric acid). The blue test paper is impregnated with litmus solution (derived from lichens) which turns red in the presence of acids; red litmus paper turns blue on contact with alkaline solutions | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / McClenaghan, Andrew |
Taille de l’image : | 3193 px × 2188 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |