You really want to know what the Hargreaves process is?
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Ok then. Read on.
The Hargreaves process was once a popular process for making potassium sulphate.
It is still used today (sometimes).
Potassium chloride is reacted with concentrated sulphuric acid to give potassium sulphate and hydrogen chloride.
This reaction takes place spontaneously because sulphuric acid is a stronger acid than hydrochloric, so it displaces hydrogen chloride from the salt.
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