XXVIII. BAKING POWDERS AND THEIR INGREDIENTS. 



1 PREPARATION OF SAMPLE.— TENTATIVE. 



Remove the entire sample from the package, mi.x carefully and pass through a 

 20-40 mesh sieve. 



TOTAL CARBON DIOXID. 



2 General Method. — Tentative. 



Make the determination by the absorption method, employing any apparatus 

 which gives accurate results when checked with pure calcite. Whatever appara- 

 tus is chosen, the tubes and materials used for absorbing and drying the carbon 

 dioxid may be varied according to the preference of the analyst. Use 0.25-1 gram 

 of sodium or calcium carbonate, according to the amount of absorbent employed, 

 and in the case of baking powder 0.50-2 grams. 



Method Using Knorr's Apparatus. — Tentative. 



3 REAGENTS. 



(a) 50% potassium liydroxid solution. 



(b) Soda lime. — Finely granulated and freed from dust by sifting. 



4 APPARATUS. 



FIG. 14 KNORR'S APPARATUS FOR THE DETERMIMATION OF CARBON DIOXID. 



This consists of a flask (.4), fitted by means of a ground-glass joint with a glass 

 connection through the upjjer part of which passes a dropping funnel (ZJ), and 

 joined at the side with a Liebig condenser (D). The mouth of the dropping funnel 



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