The most commonly used diagnostic tool for tuberculosis is a simple skin test, though blood tests are becoming more commonplace. A small amount of a substance called PPD tuberculin is injected just below the skin of your inside forearm. You should feel only a slight needle prick.
The structure has a double bond and an adjacent atom with a lone pair, so it could have resonance. The possible resonance structures are below. The first structure has the most common bonding pattern for all of its atoms, so it is a reasonable Lewis structure.
There are two possible resonance structures. These arise from the central carbon atom having a single covalent bond to one oxygen, and a double covalent bond to the other. The â¦ hydrogen-carbon bond is a single, and this doesn't change.