Question

define french degree of hardness​

Answer 1

A Clark degree (°Clark) or English degrees (°e or e) is defined as one grain (64.8 mg) of CaCO3 per Imperial gallon (4.55 litres) of water, equivalent to 14.254 ppm. A French degree (°fH or °f) is defined as 10 mg/L CaCO3, equivalent to 10 ppm.