The wood ash sample (0.5 g) was mixed with 50 ml of distilled water and agitated for 48 h.
The mixture was filtered through 0.2 mm membrane filter and titrated with 500 mol m3 HCl using 713 Metrohm pH Meter with Pt 1000/B/2/3 MKCl combined electrode.
Based on titration, soluble alkalinity was determined by measuring the number of mmol of HCl required to neutralize 1 g of ash leachate to pH 7.