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Definition: These are all alkali substances. They have a pH of more than
7, up to pH14.
You can find these substances in your homes. Bleach is a very strong alkali (pH10-12). These substances all have different pHs. If you pour, for example, bleach on your hands, it will feel soapy. But it can be very dangerous because the alkali can go through the skin and burn inside your hands.