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Applied Chemistry and Physics
Published in Robert A. Burke, Applied Chemistry and Physics, 2020
Most acids are produced by dissolving a gas or a liquid in water. For example, hydrochloric acid is derived from dissolving hydrogen chloride gas in water. All acids contain hydrogen. This hydrogen is an ion (H+) and can be measured by using the pH scale (Figure 3.138), which, in simple terms, measures the hydrogen ion concentration of a solution. Acids as a group have high hydrogen ion concentration. Bases have very low hydrogen ion concentrations and high hydroxyl (OH−) concentrations. The strength or weakness of an acid or base is the amount of hydrogen ions or hydroxyl ions that are produced as the acid or base is produced. If the hydrogen ion concentration in an acid is high, then the acid is a strong acid. If the hydroxyl concentration is high, then it is a strong base. In both cases, there is almost total ionization of the material dissolved in water to make the strong acid and base. For example, hydrochloric acid is a strong acid with a pH of 1.1; almost all of the hydrogen chloride gas is ionized in the water. If the hydrogen ion concentration is low, then the acid is a weak acid. Acetic acid is a weak acid with a pH of 3; only about 2% ionization has occurred in producing the compound.
Basic Water Chemistry
Published in Frank R. Spellman, Handbook of Water and Wastewater Treatment Plant Operations, 2020
Important Point: An acid is a substance that produces hydrogen ions (H+) when dissolved in water. Hydrogen ions are hydrogen atoms stripped of their electrons. A single hydrogen ion is nothing more than the nucleus of a hydrogen atom.
Understanding and Recognizing Corrosion
Published in Neville W. Sachs, Practical Plant Failure Analysis, 2019
The pH value of a solution is a measure of the relative number of hydrogen ions in the solution and Figure 7.6 shows a pH scale. It is the common measurement used to express whether a material is acidic or alkaline and the scale ranges from 0 to 14. A low pH indicates the material is very acidic while a high pH indicates that the material is alkaline (basic).
Water quality assessment of Mansbal Lake in Kashmir
Published in Water Science, 2022
Daawar Bashir Ganaie, Anirudh Malhotra, Irfan Ahmad Wani
pH (power of hydrogen/ hydrogen ion activity or concentration) scale is used to analyze the acidity or basicity of a given solution/liquid. The scale measures the values from 1 to 15, values being below 7 pH are categorized as acidic, while above 7 pH as basic and 7 pH denotes as neutral. Hydrogen ion concentration (pH) is well defined as the decimal logarithm of the reciprocal of the hydrogen ion activity (Covington, Bates, & Durst, 1985). pH that maintains the acidic or basic property, is a vital characteristic of any aquatic ecosystem since all the biochemical activities and retention of physicochemical attributes of the water are greatly dependent on the pH of the surrounding water (Jalal & Sanal Kumar, 2013). In the present study, the pH values ranged between 8.9 pH and 7.6 pH showing alkaline nature of water, indicating the lake was well buffered during this period of study. The highest pH values in all the months were recorded at Kondabal site 2 because of the calcium intrusion and heavy pollution load from the near catchment area. This inconstancy in pH values can be attributed to the influence of the variations in photosynthetic and decomposition rates of organic matter due to high pollution, and this statement also goes well with the findings of (Shah, Pandit, & Shah, 2017).
The physicochemical properties and microstructural characteristics of peat and their correlations: reappraisal
Published in International Journal of Geotechnical Engineering, 2021
Abhinaba Paul, Monowar Hussain, Badiga Ramu
pH is a chemical property which indicates the acidity or alkalinity of a soil. It is the logarithmic of reciprocal of hydrogen ion concentration. Basically, a hydrogen ion is an acid cation and its greater concentration in solution indicates lower pH value. Therefore, a lower pH value of peat possesses the higher acidic nature. The acidity of the peat depends on the types of rock, types of plants, the supply of oxygen and concentration of humic acid. In peatland, the acidity is a product of two phases viz. microbial decay process and cation exchange capacity. In the first phase, bacteria and fungi break down the dead roots, fibre, plants and release acid solution into surrounding area. In the second phase, the dominant presence of peat moss (partially decomposed dead vegetation) acidifies its surrounding by cation exchange. The accumulation of organic matter, decomposition, gradual release of humic and fulvic acid might be another reason for the acidity of peat. Generally, pH of sapric peat is more than the fibrous and hemic peat (Wong, Hashim, and Ali 2008; Huat, Maail, and Mohamed 2005; Kazamian, Huat, and Moayedi 2012; Kolay et al. 2011; Aminur, Kolay, and Taib 2009). Table 4 illustrated the pH value of different types of peat, which varies from 3.2 to 7.2.
Medium-chain-length poly-3-hydroxyalkanoates-carbon nanotubes composite as proton exchange membrane in microbial fuel cell
Published in Chemical Engineering Communications, 2019
Hindatu Yusuf, M. Suffian M. Annuar, Syed Mohammad Daniel Syed Mohamed, Ramesh Subramaniam
Approximately 5 mL of the anolyte was withdrawn at an interval of 24 h to determine the chemical oxygen demand (COD), ammoniacal nitrogen (NH3N), pH, and conductivity of the POME wastewater. The COD and NH3N were determined using the standard method for the examination of water and wastewater (APHA 2012). The COD results were reported in terms of % COD reduction calculated using Equation (7) while NH3N concentration was determined by phenate method and estimated from the NH3N standard calibration. The columbic efficiency (CE) was determined using Equation (8). Hydrogen ion concentration was monitored using a pH meter (Mettler-Toledo, Greifensee, Switzerland). The conductivity was monitored using a conductivity meter (model S230, Mettler-Toledo, Greifensee, Switzerland): where CODi and CODf are the initial and the final COD of the effluent in the anode, respectively. where M is the molecular weight of glucose (180 g/mol), F is the Faraday constant (96,485 C/mol), b (24) which is the number of electrons exchanged per mole of glucose, Van is the volume of the anode electrolyte (0.1 L), and ΔCOD is the change in the COD over time t (s) (Ayyaru and Dharmalingam, 2011).