Calculate the alkalinity for each water sample. Show your calculations. Summarize the data in a figure? Ans: Total alkalinity (mg/L as CaCO3) = A × N × 50000 sample(mL) Where, A=total titrant (mL) N= normality 5000= conversion factor to change normality into units of CaCO3 For GroundWater- A= 32.
5mL=0.0325L N= 0.02mg/L Sample=50mL= 0.05L Totalalkalinity =0.0325L × 0.02 mg/L × 50000 = 650 mg/L 0.05L ForSurface Water- A= 14.
5 mL= 0.0145L N= 0.02mg/L Sample =50 mL =0.05L Totalalkalinity = 0.0145L ×0.02mg/L × 50000 =290mg/L 0.05L ForUnknown Water Sample- A= 1.
2mL= 0.0012L N= 0.02 mg/L Sample=50 mL= 0.05L Totalalkalinity = 0.0012L ×0.
02mg/L × 50000 =24mg/L 0.05L 2.Whatis one source of error for this analysis and how can it be avoided?2.
Ans:-this analysis is very much easy to perform, but in terms of error, some pointswe should keep in mind to avoid error,1. the toomuch fast addition of the sulfuric acid may cause to skip the exact reading.2. thestopcock and tip of the burette should be filled to get right reading becauseone or two drops can make a big difference.
The positionof delivery tip should be always under the solution being titrated. 3. therinsing of the burette with acid can also effect the calculation of alkalinity.3.Basedon your knowledge of the chemistry of different sources of water, explain thedifferences in alkalinity that you found. Where the results what you expected?Comment on the unknown water sample.
Where might this water source have comefrom.3. The watercollected or usually present at different sources called as surface wateralways have different range of the alkalinity as the water comes from rocks orponds usually will have high alkalinity as the carbonate, bicarbonate andhydroxide ions from those rocks joins water. The results are very much close tomy expectations. As the range of alkalinity of surface water is high.But theground water passes from sandstone and granite will have low alkalinity, theexpected value of the alkalinity of groundwater is low as in my lab Icalculated.The unknownsample provided to us to calculate the alkalinity had very low alkalinity and Iguessed it could be the rain water, I was not exactly right but it was snowthat turned to water at room temperature.4.
You are working in a lab that routinely doesalkalinity analyses. You usually buy0.02 N sulfuric acid from Hach, but this time your boss orders pure sulfuricacid from Sigma-Aldrich. You have tomake 5 L of 0.02 N sulfuric acid to do a series of alkalinity titrations. Describe how you would make thesolution. Show all calculations. 4.
Ans:-The Normality of sulfuric acid = 0.02N Volumerequired = 5L Equivalentmass of sulfuric acid= 49g Now,compound needed (in grams) = 0.02 × 49 × 5 = 4.9g Volume ofacid required = grams of acid needed Conc. % × specific gravity As specificgravity is known as, 1.84 and concentration of sulphuric acid is 97% Volume= g =2.74 ml 0.97 × 1.
84 5.Explain how alkalinity is different from hardness. Alkalinity Hardness 1.It is ability of a solution to neutralize the acids such as bicarbonates, carbonates and hydroxide ions. 1.
It is sum of multivalent metal ions present in solution. 2. it is expressed as the concentration of calcium carbonate ions in water. 2. it also expressed the concentration of CaCO?. The alkalinity comes from limestone and dolomite dissolved in water as it passes from rocks, but the calcium part causes hardness of water.
3. whereas the carbonate part causes alkalinity of water. 4. This have vital effect on toxicity caused by copper (used to treat algae and parasites) in water. 4. it should be minimum as for development of species of fish that originates in soft water. 6. What is the difference betweenphenolphthalein alkalinity and total alkalinity?6.
Ans:- Phenolphthalein alkalinity Total alkalinity 1. This is measure of only hydroxides and half carbonates. It aslo called as carbonate alkalinity. 1.This is determined by amount of bicarbonate, carbonate and cyanurate ions.
2. To titrate the water sample with acid titrant to phenolphthalein end point is called phenolphthalein alkalinity. 2.This is ability of water to resist a pH change.
3. pH should be known to determine carbonate alkalinity. 3.It is used a key parameter in the maintenance of balance of water. 4. In this the phenolphthalein changes color at pH 8.
2 – 8.3..
4.High total alkalinity is important as it helps to keep pH stabilised around 4.2- 4.5. 5. Reaction for total alkalinity is (?OH- – H+?) + HCO3- + 2 CO3-2 5.
Reaction for total alkalinity is (?OH- – H+?) + CO3-2 – H2CO3* 7.Whyis alkalinity important for drinking water treatment? What might happen to thetreatment processes if the alkalinity of the water was low? How would thisimpact treatment?7. Ans :- The presence of hydroxides, bicarbonates andcarbonates present in water cause alkalinity. Bi carbonates among these ionshas biggest effect on alkalinity of water. The high alkalinity will change thetaste of water as soda water, The limit of alkalinity in water is limited by EPAdrinking water regulations in terms of TDS (total dissolved solids) is 500ppmand in terms of PH is should be around 7.
Importanceof alkalinity: -1.The alkalinity is very much important for aquaticanimals as it saves them from damage which can be done by rapid change occur inwater. 2.In the coagulation high alkalinity will causeformation of floc and flocculation also can be effected by alkalinity change asthis will cause to make water more heavier by binding of the destabilizedparticles by coagulation.
While water suffering low alkalinity we should treatit by neutralizing filter, in this process we add neutralising material toraise pH of water. But it may cause a problem of hardness in water as the useof magnesium oxide to raise pH of water but also hardness. To get rid of thiswe should backwash the neutralising filter time to time and also theinstallation od cartridge filter prior to neutralising filter will removesolids from water. By doing so neutralising filter will work for long time. Thewater softener should be used to remove hardness. We also have to keep in mindthat use of sodium as softener may not be suitable for people need low sodiumdiet. We can alternatively use soda ash and sodium hydroxide which will notcause hardness and will raise the pH and make it neutral.
The acid injections also help to neutralise water andminimises the chances of pipe corrosion.