46 
LABORATORY MANUAL 
Observations: 
Sample 
cc. milk 
cc. n /i 0 NaOH 
% acidity 
1 
a 
b 
c 
2 
a 
b 
c 
' 
3 
a 
b 
c 
Conclusions: 
Questions: (1) What will be the effect if a bottle of NaOH solution is 
left unstoppered? 
(2) What is the cause of acidity in milk? What is the average 
acidity of fresh milk? 
(3) How is the phenolphtalein indicator solution prepared? 
(4) If 20 cc. of cream require 15 cc. n / i0 NaOH solution for neutrali¬ 
zation, what is the per cent acid in the sample? 
References: F. & W. ^ 128-152, inclusive; Van S. 131-151; Jud. pp. 
102-106; St. pp. 132-136. 
