pH waa cabir lagu cabiro darajada Aashitada ama Base-ka ee Milan, Wuxuuna u dhaxeeyaa 1 - 14, waxaana dexdhexaad u ah 7 (Neutral). PH waxaa markii ugu horeysay soo saaray kimistari yaqaankii reer Danish (Søren Peder Lauritz Sørensen) isagoona ku baaray Sheybaarka (Carlsberg Laboratory) sanadkii 1909.