Editing PH (section)

=== pH Indicators ===
{| {{table|class=floatright}}
|+ Average pH of common solutions
|-
!Substance
!pH range
!Type
|-
|[[Sulfuric acid|Battery acid]]
| style="background-color: #CC0000; text-align: center; color: #ffffff" |< 1
| rowspan="6" style="text-align: center" |[[Acid]]
|-
|[[Gastric acid]]
| style="background-color: #EE0000; text-align: center; color: #ffffff" |1.0–1.5
|-
|[[Vinegar]]
| style="background-color: #FF4000; text-align: center" |2–3
|-
|[[Orange juice]]
| style="background-color: #FF6600; text-align: center" |3.3–4.2
|-
|[[Coffee|Black coffee]]
| style="background-color: #ffff00 ; text-align: center" |5–5.03
|-
|[[Milk]]
| style="background-color: #99cc33; text-align: center" |6.5–6.8
|-
|[[Pure water]] at 25&nbsp;°C
| style="background-color: #339933; text-align: center; color: #ffffff" |7
| style="text-align: center" |Neutral
|-
|[[Sea water]]
| style="background-color: #19cdff; text-align: center; color: #000000" |7.5–8.4
| rowspan="4" style="text-align: center" |[[Base (chemistry)|Base]]
|-
|[[Ammonia]]
| style="background-color: #3333ff; text-align: center; color: #FFFFFF" |11.0–11.5
|-
|[[Bleach]]
| style="background-color: #330099; text-align: center; color: #FFFFFF" |12.5
|-
|[[Lye]]
| style="background-color: #330066; text-align: center; color: #FFFFFF" |14
|}
{{Main|pH indicator}}
pH can be measured using indicators, which change color depending on the pH of the solution they are in. By comparing the color of a test solution to a standard color chart, the pH can be estimated to the nearest whole number. For more precise measurements, the color can be measured using a [[Colorimeter (chemistry)|colorimeter]] or [[spectrophotometer]]. A [[Universal indicator]] is a mixture of several indicators that can provide a continuous color change over a range of pH values, typically from about pH 2 to pH 10. Universal indicator paper is made from absorbent paper that has been impregnated with a universal indicator.  An alternative method of measuring pH is using an electronic [[pH meter]], which directly measures the voltage difference between a pH-sensitive electrode and a reference electrode.