$^{1}$Notes
$^{\text{2:Page num}}$Chemistry - Years 4 and 5 (Oxford)
$^3$https://www.khanacademy.org/science/chemistry/acids-and-bases-topic/acids-and-bases/a/arrhenius-acids-and-bases
$^4$https://www.khanacademy.org/science/chemistry/acids-and-bases-topic/acids-and-bases/a/bronsted-lowry-acid-base-theory
$^5$https://www.britannica.com/science/pH
$^6$https://www.khanacademy.org/science/chemistry/acids-and-bases-topic/acids-and-bases/a/ph-poh-and-the-ph-scale