pH

The sour taste o lemon juice is a result o it bein componed o aboot 5% tae 6% citric acid, an acid wi a pH o roughly 2.2.

In chemistry, pH (/piː eɪtʃ/ or /piː heɪtʃ/) is a measur o the acidity or basicity o an aqueous solution. Solutions wi a pH less nor 7 are said tae be acidic an solutions wi a pH greater than 7 are basic or alkaline. Pure watter haes a pH very close tae 7.

The pH scale is traceable tae a set o staundart solutions whose pH is established bi internaitional agreement. Primary pH staundart values are determined uisin a concentration cell wi transference, bi measurin the potential difference atween a hydrogen electrode an a staundart electrode sic as the silver chloride electrode. Measurment o pH for aqueous solutions can be duin wi a glass electrode an a pH meter, or uisin indicators.

pH measurements are important in medicine, biology, chemistry, agricultur, forestry, fuid science, environmental science, oceanography, ceevil ingineerin, chemical ingineerin, nutrition, watter treatment & watter purification, an mony ither applications.

Mathematically, pH is the negative logarithm o the activity o the (solvatit) hydronium ion, mair eften expressed as the measur o the hydronium ion concentration.