Alkalinity Buret Titration

[@Sassenach317]

Could you explain why some labs would use Methyl Purple Indicator Solution for Total Alkalinity Testing vs. using Methyl Orange, or Bromocresol Green-Methyl Red Indicator?

[@Sahity]

@aquaphoenixsci this is a good one

[@Trudeautthebestt]

@@Sahity i believe that both of them have different pH valve. so purple will turn color to purple at pH 4 and i think orange turn red at 3pH thats all but i think using any will be fine cause it show low pH hope that helps

[@johnkimuelbello3453]

What was the sulfuric acid concentration used for the titrant?

[@AquaPhoenixSci]

Hi John. For this test it was Sulfuric Acid 0.02N (N/5O). You can see the complete reagent set online here: catalog.aquaphoenixsci.com/product/alkalinity-pt-reagent-set

[@bharatbhushan8191]

Sir why we multiply by 20

[@AquaPhoenixSci]

You multiply the number of milliliters by 20 because that is the equivalency for this titration. When you titrate a 50mL sample with Sulfuric Acid 0.02N (N/50), each milliliter of titrant used will be equivalent to 20ppm of alkalinity expressed as Calcium Carbonate in your sample.

[@rajamurugan2356]

What if I titrate 100 mL sample with 0.02 N H2SO4 or 0.02 N HCl. What is the conversion factor? Then how to calculate the conversion factor from the given information such as, Concentration of titrant and volume of the sample.

[@Trudeautthebestt]

@@rajamurugan2356 u still times by 20 the sample doesnt matter. for each ml of the acid u times by 20 not the water sample