Date : 17/03/2022
Principle of Normality and Dimension of Known Normalization in Limestone Soil –
Volume HCI The amount of HCI left after chemical reaction can be quantified with standardized NaOH titration. As much as HCI was used for the reaction, its equivalent is in the limestone clay sample.
CaCO3 + 2HCI – CaCl₂ + H₂O + CO₂. HCL 2 NaOH 0.25 N 3. Phenolptheliine
Procedure :
- Take sample according to soil type, take 5g soil if it is heavy black soil, take 10g soil if it is light sandy soil.
Weigh, place in a conical pan.
2. Pour into a 50ml 0.5NHCI
3. Place the glass lid on the pan and heat slowly. Heat for 5 minutes until slightly boiling point.
4. Strain through a filter paper. Cover the entire soil with sieve paper. Add a little water and acidify all the soil and filtration paper. Titrate against NaoH solution . Suppose the standard sodium for titration is No.5 at 90ml
Calculations :
meq =
meq = Hydrochloric Acid ( Volume ml X normality ) – Sodium Hydroxide ( Volume ml X normality )
= 50 ml x 0.5 N – 12.5 ml x 0.25 N
= 25.0 meq – 3.125
5 g soil = 21.875
100 g soil = 437.5 meq of caco3
meq Caco3 x Equivalent weight of Caco3
= 43705 x 50
= 21875 mg
21.875 gm of Caco3 in 100 gm Soil .
