Experiment 1: Determination of pH of Water

pH is a measure of the acidic or alkaline condition of water and is calculated as pH = -log {H+}.

The equilibrium constant for water at 25°C is Kw = 10^-14.

The pH of deionized water is 7.0 at 25°C because the concentration of hydrogen ion and hydroxyl ion is both 10^-7 M.

<p>A pH value of less than 7 indicates acidity.</p> Signup and view all the answers

<p>Groundwater is often slightly acidic due to the presence of excess carbon dioxide.</p> Signup and view all the answers

<p>The activity of water is considered as a constant and its activity is taken as 1.0 in the equation Kw = {H+}{OH-}.</p> Signup and view all the answers

<p>pH meter, 200 mL beaker, wash bottle, tissue paper</p> Signup and view all the answers

<p>To reduce changes in the sample and maintain its integrity.</p> Signup and view all the answers

<p>Temperature can change the electrode output and the inherent pH of the sample.</p> Signup and view all the answers

<p>Biological activity continues, leading to changes in the sample.</p> Signup and view all the answers

<p>Noting pH and temperature, using temperature compensation or calibration.</p> Signup and view all the answers

<p>Buffers are used to calibrate the pH meter since their pH values are known.</p> Signup and view all the answers

<p>The presence of coloured solutes</p> Signup and view all the answers

<p>Precipitation of dissolved constituents (e.g., Fe)</p> Signup and view all the answers

<p>Light absorbing materials can cause low readings</p> Signup and view all the answers

<p>Floating debris and coarse sediments</p> Signup and view all the answers

<p>Finely divided air bubbles</p> Signup and view all the answers

<p>Dilute the sample with turbidity-free water</p> Signup and view all the answers

<p>To monitor the quality of water and assess any potential issues.</p> Signup and view all the answers

<p>Presence of color in water, usually from natural organics, can lead to the formation of harmful byproducts during disinfection.</p> Signup and view all the answers

<p>To prevent the formation of harmful disinfection byproducts like tri-halomethanes.</p> Signup and view all the answers

<p>15 Pt-Co Unit</p> Signup and view all the answers

<p>By comparing the color produced by 1 mg/l of platinum and 0.5mg/l of cobalt to the standard color solution.</p> Signup and view all the answers

<p>Yellow-brownish</p> Signup and view all the answers

<p>The turbidity of the original sample is calculated by multiplying the turbidity of the diluted sample by the dilution factor, which in this case is 6 (5 volumes of water + 1 volume of sample). Therefore, 30 NTU x 6 = 180 NTU.</p> Signup and view all the answers

<p>Turbidity is important in filtration processes because high turbidity levels can clog filters quickly and reduce their efficiency, leading to the need for more frequent filter replacements.</p> Signup and view all the answers

<p>Turbidity is important in disinfection processes because particles in turbid water can shield harmful microorganisms from disinfectants, reducing the effectiveness of the disinfection process.</p> Signup and view all the answers

<p>Common methods for removing turbidity from water include sedimentation, coagulation, flocculation, and filtration.</p> Signup and view all the answers

<p>Materials that cause turbidity in polluted river water include suspended particles like silt, clay, organic matter, and microorganisms.</p> Signup and view all the answers

<p>The typical limit placed on turbidity in water supplies is 1 NTU. This limit is set to ensure that water is visually clear and to prevent interference with disinfection processes.</p> Signup and view all the answers