Vegetable oil, like this olive oil, does not have a pH value. Neither does any other pure oil or other liquid that does not contain water.
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Question: What Is the pH of Vegetable Oil?
Actually, you can't measure the pH of vegetable oil because it doesn't have one! pH is a measure of the hydrogen ion concentration in an aqueous solution (water). Because there is no water in vegetable oil, there is no pH value.
More About pH
How To Calculate pH
pH of Water
What Does pH Stand For?