e per cent of solids. Observe the appearance of the solids. Test both
samples and compare.

1. How may the per cent of solids in vinegar be determined? 2. Describe
the appearance of the solids from the good and from the poor sample of
vinegar. 3. What is the legal standard for vinegar solids in your state?

Experiment No. 35

Specific Gravity of Vinegar

Pour 170 cc. vinegar into 200 cc. cylinder. Place a hydrometer for heavy
liquids (sp. gr. 1 to 1.1) in the cylinder. Note the depth to which it
sinks and the point registered on the scale on the stem. Note
temperature of vinegar. Record specific gravity of vinegar.

1. What effect would addition of water to vinegar have upon its specific
gravity? 2. What effect would addition of such material as sugar have
upon specific gravity? 3. Why should the specific gravity of vinegar be
fairly constant? 4. What would be the weight of 1000 cc. of vinegar
calculated from the specific gravity?

Experiment No. 36

Acidity of Vinegar

Into a small beaker pour 6 cc. of vinegar and 10 cc. of water and a few
drops of phenolphthalein indicator. Run in standard KOH solution from a
burette until a faint pink tinge remains permanently. Note the number of
cubic centimeters of KOH solution required to neutralize the acid.
Divide this number by 10, which will give approximately the per cent of
acetic acid.

1. How may the per cent of acidity of vinegar be determined? 2. Why was
phenolphthalein used? 3. Why was KOH used? 4. What acids does vinegar
contain? 5. What is the legal requirement in this state for acetic acid
in vinegar? 6. How did the acidity you obtained compare with this legal
requirement?

Experiment No. 37

Deportment of Vinegar with Reagents

To 10 cc. of vinegar in a test tube add 8 or 10 drops of lead
sub-acetate and shake. Observe the precipitate. Lead sub-acetate
precipitates mainly the malic acid which is always present in cider
vinegar.

1. How may the presence of malic acid in a vinegar be detected? 2.
Describe the precipitate. 3. What does malic acid in a vinegar indicate?

Experiment No. 38

Testing Mustard for Turmeric

Place 1 gm. of ground mustard on a small watch glass and moisten
slightly with water. Add 2 or 3 drops of NH_{4}OH, stirring well with a
glass rod. A brown color indicates turmeric present in considerable
quantity.

Test a sample of good mustard and one adulterated with turmeric and
compare the results.

Experiment No.