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Soil pH is a measure of the acidity or basicity (alkalinity) of a soil. Soil pH is a key characteristic that can be used to make informative analysis both qualitative and quantitatively regarding soil characteristics. [ 1] pH is defined as the negative logarithm (base 10) of the activity of hydronium ions ( H+.
A pH indicator is a halochromic chemical compound added in small amounts to a solution so the pH ( acidity or basicity) of the solution can be determined visually or spectroscopically by changes in absorption and/or emission properties. [ 1] Hence, a pH indicator is a chemical detector for hydronium ions (H 3 O +) or hydrogen ions (H +) in the ...
Universal indicator. A universal indicator is a pH indicator made of a solution of several compounds that exhibit various smooth colour changes over a wide range pH values to indicate the acidity or alkalinity of solutions. A universal indicator can be in paper form or present in a form of a solution. [ 1]
At 25 °C (77°F), solutions with a pH less than 7 are acidic, and solutions with a pH greater than 7 are basic. Solutions with a pH of 7 at 25 °C are neutral (i.e. have the same concentration of H + ions as OH − ions, i.e. the same as pure water). The neutral value of the pH depends on the temperature and is lower than 7 if the temperature ...
Nitrogen dioxide is a chemical compound with the formula NO2. One of several nitrogen oxides, nitrogen dioxide is a reddish-brown gas. It is a paramagnetic, bent molecule with C 2v point group symmetry. Industrially, NO2 is an intermediate in the synthesis of nitric acid, millions of tons of which are produced each year, primarily for the ...
Red soil is a type of soil that typically develops in warm, temperate, and humid climates and comprise approximately 13% of Earth's soils. [1] It contains thin organic and organic-mineral layers of highly leached soil resting on a red layer of alluvium. Red soils contain large amounts of clay and are generally derived from the weathering of ...
Raising the water's pH level, e.g. by adding baking soda, will accelerate the process of leaching. [26] Softwoods, while in general much lower in tannins than hardwoods, [27] are usually not recommended for use in an aquarium [28] so using a hardwood with a very light color, indicating a low tannin content, can be an
Thymol blue (thymolsulfonephthalein) is a brownish-green or reddish-brown crystalline powder that is used as a pH indicator. It is insoluble in water but soluble in alcohol and dilute alkali solutions. It transitions from red to yellow at pH 1.2–2.8 and from yellow to blue at pH 8.0–9.6.