[Chem 26.1] Experiment 6

Standardization of 0.01 M EDTA Solution (Step 1)

Pipette 10.00 mL of 0.0050 M working CaCO₃ into 250-mL Erlenmeyer flask, then add 75 mL distilled water

Standardization of 0.01 M EDTA Solution (Step 2)

Add 3 mL buffer solution and 2-3 drops of EBT indicator, then titrate with 0.0100 M working EDTA solution

Standardization of 0.01 M EDTA Solution (Step 3)

Record initial volume, then titrate until wine red color turns to clear blue

Standardization of 0.01 M EDTA Solution (Step 4)

Record final volume

Analysis of Mineral Water Sample (Step 1)

Pipette 50.0 mL commercial mineral water into 250-mL Erlenmeyer flask

Analysis of Mineral Water Sample (Step 2)

Add 3 mL buffer solution and 2-3 drops of EBT indicator, then titrate with 0.0100 M working EDTA solution

Analysis of Mineral Water Sample (Step 3)

Record initial volume, then titrate until wine red color turns to clear blue

Analysis of Mineral Water Sample (Step 4)

Record final volume

Analysis of Tap Water Sample (Step 1)

Open faucet source for 1 min, then rinse glass bottle. Collect water sample and allow to overflow. Secure glass bottle with parafilm.

Analysis of Tap Water Sample (Step 2)

Pipette 50.0 mL tap water into 250-mL Erlenmeyer flask

Analysis of Tap Water Sample (Step 3)

Add 3 mL buffer solution and 2-3 drops of EBT indicator, then titrate with 0.0100 M working EDTA solution

Analysis of Tap Water Sample (Step 4)

Record initial volume, then titrate until wine red color turns to clear blue

Analysis of Tap Water Sample (Step 5)

Record final volume

Soft

0-20 ppm CaCO₃

Moderately soft

21-60 ppm CaCO₃

Moderately hard

61-120 ppm CaCO₃

Hard

121-180 ppm CaCO₃

Very hard

>180 ppm CaCO₃