University:
Arizona State University
Course:
BIO 130 | Environmental Science
Academic year:

2024
Views:

143

Pages:

2
Author:

Thuyoul US

DETERMINATION OF ALDD AND THE NEUTRALIZING POWER OF LIME 1. Determination of the amount of aluminum that can be exchanged. The determination of interchangeable Al (Al-dd) is carried out by the titration method. Interchangeable and soluble Al in soil solution can be set in amount according to the following reaction: Liat – Al + K+ Liat-K + Al3+ Al3+ + NaOH Al(OH)3 Al(OH)3 + 6 FAlF63- + 3 OHOH- + H + H2O How it works : The stages of the Work are as follows: 1. Weigh 5.0 g of soil, put in 125 ml of erlenmeyer 2. Add 50 ml of 1.0 N KCl solution, beat with a whisk during 30 minutes 3. Strain and collect the filtrate 4. Pipette 25 ml filtrate, put it in a 125 ml erlenmeyer 5. Add 5 drops of phenolptalein indicator solution 6. Titration with 0.1 N NaOH until a permanent pink color appears. Up to this stage the amount of NaOH added has neutralized H+ and Al3+ 7. Add approximately one drop of 0.1 N HCl until the pink color disappears again 8. Add 10 ml of 4% NaF, the red color will reappear 9. Titration again with 0.1 N HCL until the red color disappears again. Record the amount of HCl required. The amount of acid used will be equivalent to the amount of Al that can be exchanged. Account: ppm Al = (ml HCL x N HCL x f.p. x 9 x 103)/dry soil weight 105°C Al/100g = ppm Al/90 2. Lime Neutralizing Power The neutralization power of lime is the ability of lime to neutralize Al-dd which is a potential contributor to acidity. The lime commonly used is agricultural lime (Calcite and Dolomite). How it works: 17 1. Add 0.5 g of lime to Erlenmeyer 125 ml 2. Add 25 ml HCl 1 N 3. Heat on a bath until dissolved, after dissolving add 50 ml of aquades 4. Add 5 drops PP 5. Titration with NaOH 1 N Account: (ml HCl x N HCl) – (ml NaOH x N NaOH) Lime neutralization power = x 100% BE CaCO3 18