Rabies is a very serious viral infection that targets the brain and nervous system. You can catch rabies if you are bitten by an infected animal and haven't been vaccinated. It's almost always fatal once symptoms develop, but can be prevented if treatment is given promptly after exposure.
**The pH scale is a measure of the hydrogen ion concentration. It spans from 0 to 14 with the middle point (pH 7) being neutral (neither acidic or basic). Any pH number greater than 7 is considered a base and any pH number less than 7 is considered an acid. 0 is the strongest acid and 14 is the strongest base.
Bases are substances that react with acids and neutralise them. They are usually metal oxides, metal hydroxides, metal carbonates or metal hydrogen carbonates. Many bases are insoluble - they do not dissolve in water. If a base does dissolve in water, we call it an alkali. Here are two examples: Copper oxide is a base because it will react with acids and neutralise them, but it is not an alkali because it does not dissolve in water. Sodium hydroxide is a base because it will react with acids and neutralise them. It's also an alkali because it dissolves in water.