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.
The general structure of an ether. R and R' represent any alkyl or aryl substituent. Ethers (/ËiËÎ¸Ér/) are a class of organic compounds that contain an ether groupâan oxygen atom connected to two alkyl or aryl groups. They have the general formula RâOâRâ², where R and Râ² represent the alkyl or aryl groups.