Now BaSO 4 : H 2 SO 4 : : 2-589 : x 



i> e., 173 + 32-06 + 4 X 1 6 : 2 + 32-06 + 4 x 16 : : 2 589 : x 

 ( = 233-06) ( = 98-06) 



98-06x2-589 253-87734 



/. x=? J * J^ ' '^=1-080 grammes in 20 c.c. 



233-06 233-06 



1,397. The Standard Sodium Hydrate: The alkaline 

 solution that has to be used for the determination of Nitrogen 

 in all analyses, should be made of such a strength, that 100 

 c. c. of it should be exactly neutralized by 20 c. c of 

 the standard sulphuric acid the strength of which has 

 been just determined. This is done in the following 

 way : 



A pipette-ful of H2SO 4 , i. e. 20 c. c., is taken in a 

 white porcelain bason. It is diluted with about 200 c. c. 

 of distilled water and coloured with an aniline colour. A 

 burette-ful of the alkaline solution is then taken, and it is 

 found, say, that the whole of the 50 c. c. of the alkaline 

 solution in the burette is taken up without neutralising the 

 acid. Another burette-ful is then taken and now, say, 

 only 2'44 c. c. z. e., 52*4 c. c. altogether, is required to 

 neutralise the acid (when the colour just disappears). The 

 whole of the alkali in the bottle is then transferred to another 

 bottle, and say, nooc. c. measured back into the former 

 bottle. Now as 52-4 of the alkaline solution requires 47-6 

 of water to make it into 100 c. c., how much water must 

 be added to the noo c. c. to make it of the proper strength ? 

 52*4 : 1 100 : : 47-6 : x 



1100x47 6 



52-4 



So 999'2 c. c. of water has to be added to the solu- 

 tion in the bottle ; and the burette filled with the new 

 solution, and the process of decolourizing the 20 c. c, of 

 H 2 SO 4 coloured with an aniline colour, repeated. After 

 2 or 3 trials the exact strength can be attained. 



Now we have seen, that i pipette of H 2 SO 4 contains 1*089 



