The Electrical experimenter

May, 1917 THE ELECTRICAL EXPERIMENTER
I.\
ACIDS, BASES, AND SALTS.
this lesson vvc shall take- up the
study of the .various acids and chariicteristics.
These form one of the
most important studies in the realm
(if chemistry. A resume of the general
properties of acids are briefly as folliuvs
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62
How Apparatus Is Arranged In Experiment of
Collecting the Product of Acetic Acid.
1. An acid is a substance composed of
hxdrogcn and a iioit-iiiclallic clciiicnt or
radical, the hydrogen being replaceable by
a metal or a group of elements equivalent
to a metal. The fact that hydrogen is a
constituent of all acids, explains why they
are sometimes called Salts of Hydrogen.
2. .Acids usually have a sour taste.
3. If soluble in water, as most acids are.
they turn blue litmus paper (or solution)
red. They also change the color of many
vegetable substances.
4. They react readily with a base to
form a salt and water.
5. They react readily with some inetals
to form salts, liberating hydrogen.
6.
7.
Most acids are
They also have
soluble in water.
the power to decompose
most carbonates, like limestone, liberating
carbon dioxid which escapes with
effervescence.
The common acids are:
Hvdrochloric (HCH: Xitric (HNC) ;
Sulfuric (H,SOJ: .Acetic (CJT.O,) ; Oxalic
(HAO,") : Tartaric (njC,ll„0,) and
Citric (CoHsO;-);
Of tbese common acids. Hydrochloric is
a cas (the Hydrochloric or Muriatic acid
of commerce is only the gaseous acid in
solution) : Sulfuric and Xitric acids are
liquids : while Oxalic, Tartaric, and Citric
acids
To
are solids.
illustrate the many familiar substances
which are acids or contain tlieni,
we will take the following few
Vinegar, Pickles and Relishes, when .Acetic
acid is present, attributes to the agreeable
sour taste.
N'inegar is simply a dilute solution of
acetic acid, containing coloring matter and
other substances, obtained by the acetus
fermentation of poor wine or wine residues,
of beer which has turned sour, and
of other dilute alcoholic liquids.
The sourness of fruits being due to the
presence of citric acid, as in the lemon,
rpnle. currant, r spberry, gooseberrv,
Durinf; fermentation many acids
etc.
are
formed, as in the ca':e of sour milk, lactic
acid is present
Experimental Chemistry
By ALBERT W. WILSDON
Twelfth Lesson
Soda water is a solution of Carbonic
acid (Carbon Dioxid), and acid phosphate
is a solution of a sour calcium pliosphatc.
.Mineral waters frequently contain Carbonic
acid.
Hydrochloric acid is present in tlie gastric
juice of tlie stomach, and performs
an important part in the process of digestion.
b'rom the above we can see that many
acids are of importance, and many are
used by us every day in some form or
otlier. We can, therefore, see that all
acids are not to be scorned as dangerous,
as doubtless many readers of this article
have heretofore believed, when the
word acid was mentioned.
XOMEXCLATURE OF ACIDS—
Oxygen is a component of most acids,
and the names ol these acids correspond to
the proportion of oxygen which they contain.
The best-known acid of an element
usually has the suffix -ic, as Sulfuric. Nitric.
Phosphoric. If an element forms another
acid containing less oxygen, this acid
has the suflnx -ous, as, Sulfurous, Chlorous,
Phosphorous. Some elements form an acid
containing less oxygen than the -ous acid:
these acids retain the suffix -ous, and
liave, also, the prefix Hypo-, as, Hyposulfurous,
Hypophosphorous, Hypochlorous.
The prefix Hypo- is derived from the
Greek word, meaning lesser or under. If
an element forms an acid containing more
oxygen than an -ic acid, such an acid retains
the suffix -ic and has, also, the pre-
In Conducting Experiments With Various
Acids it Will be Found Convenient to Place
the Test Tubes Containing the Acids In a
Wooden Rack. The Tubes May Be Suitably
Labeled.
fix Per, as, Persulfuric, Perchloric. The
Latin prefi.x meaning beyond or over. The
few acids wliich contain no oxygen have
the prefix Hydro- and the suffi.x -ic. as,
I lydrochloric, Hydrobromic, Hydrofluoric.
It should be noticed that these suftixes arc
not always added to the name of the element,
but often to some modification of it,
.\cids having the prefix Hydro- and ending
in -ic form salts with names ending in
-ide and having no prefix.
.All other acids with names ending in -iV
form salts with names enilin,g in -ate.
[I'inal "e" dropt in simplified spelling.]
.AH acids who:e names end in -ous, form
salts whose names end in -ite.
ACIDS /v:-'!^ THEIR SALTS.
Hydrochloric acid. HCl; Form Clilorids. NaCl;
Po'lium Chlorid.
Sulfuric aci I. H^SOj; Form Sulphats. CUSO4;
Co'ipcr .'^ulpliat.
Nitric aril. llNO.i; Form Xitrats PbtNOslj;
1 eai Nitrat.
Sulfuroin acirl. H''-"0,i: Form .Sulphits. KrSOj;
Potassium Fulphit.
Hydrobromic acil. HBr: Form bromide, .AfiBr:
Silver Broinid.
Carbonic acid. I^.'CO.i; Form Carbonats CaC03;
Calcium Carbonat.
Hydro^ulfuric arid. H2S; Sulphids. ZnF;
7inc Sulphid.
43
Hydroiodic acid.HI; Form lodids, KI;Potas3iumIodid
Nitrous acid. H.VOa; .Nitrits. NaNOa;
Sodium Nitrit.
Phosphoric acid. lljPOa; Form Phosphats. FeP04;
Iron Phospliat.
Hydrofluoric acid, HF: I'orm Fluorids, CaFj;
Calcium Fluorid.
Chloric acid, HCIO3; Form Chlorals. KClOj;
Potassium Chloral.
The nomenclature of acid; is well i'.lu -
trated Ijy the s-ries of chlo.-in acids:
Name. Formula.
Hydrochloric HCl
Hypochlorous HCIO
Chlorous HCI02
Chloric HCIO3
Perchloric HCIO4
Xot all elements form a comp!ete series
of acids, but the nomenclature usually
agrees with the above principles.
-An examination of tlie formulas of acids
show that all do not contain the san.e number
of hydrogen atoms. .Acids are sometimes
classified by the number of hydrogen
?toms which can be replaced by a
metal. The varying power of replaceab'ility
is called Basicity. A Monobasic Acid contains
only one atom of replaceable hydrogen
in a molecule, as Xitric .Acid H.XO.
A molecule of -Acetic acid (CjH,0,) contains
four atoms of hydrogen, but for reasons
which are too complex to state here,
only one of these atoms can be replaced by
a metal. Dibasic and Tribasic Acids contain
two and three replaceable atoms, as.
Sulfuric acid (HjSO,) and Phosphoric
acid (H., PO,). Obviously, monobasic acids
form only one class of salts, dibasic acids
form two classes, tribasic acids form three,
etc.
EXPERIMEXT NO. 51
ImII a test tube one-third full of either
Hydrochloric -Acid (diluted), or Sulfuric
.Acid (diluted). Fill another test tube onethird
full of concentrated acetic acid. In
some manner label the tubes for identification
of the contents.
Try the action of a drop of tb.e acid on
both red and blue litmus paper.
Drop a small piece of zinc or other metal
into each tube successively. If no chemical
action results, warm gently. Test for
the most obvious product (hydrogen") by
holding a lighted match at the mouth of
each tube. If no decisive action results,
provide the test tube with a stopper and
simple delivery tube, and collect any product
in a test tube over water. This lat-
Slmple Method of Dropping Liquids by Means
of a G ass Rod Held In the Hand.
ter method will probably be unnecessary
except with the acetic acid.
(Continued or. page 52)