Water analysis

Determination of Residual Chlorine

Principle:
In a neutral or slightly alkaline solution, Potassium Chromate can
indicate the end point of silver nitrate solution.Silver chloride is precipitated
Quantitatively before red silver chromate is formed.Estimation of chlorine by
this method is known as Argento metric Titration.
Reagents:
* Potassium Chromate solution
* Standard Silver Nitrate Titrant
* Standard sodium chloride solution
Procedure:a) sample Preparation
* [....]

Determination of Mixed Liquor Suspended Solids

Apparatus :
* Furnace
* Whatman Filter paper No – 42
* Silica Crucible
* Funnel
Procedure :
* Take 20 ml of aerated sample and filter it through Previously weighed whatman paper No – 42
* Wait for complete filtration by giving 2-3 washings with distilled water.
* After complete filtration keep the paper in oven at 1000C for [....]

Calculation of Normality

Equivalent weight (EW) = Molecular weight (MW) / Valencey. (Z)

Normality (N) = Equivalent weight (EW) / Volume of Solution (1000 ml.)

Meq = Actual weight (W) / Equivalent weight (EW)

Example:Molecular wt of K2Cr2O7 is 294.148 gm

Valency = 6 (because of Cr -6)

EW = 294.148/6 = 49.025

N = 49.025/1000 [....]