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|  MIL-L-14758 (MU)
azide as follows:
Percent lead azide = 0.1558 (A-B) (C-D)
(273 plus or minus t)w
where:
A
=
ml. of gas measured in gas burette
B
=
ml. of water added to reaction flask
=
C
atmospheric pressure in mm. of mercury
=
D
vapor pressure of water in mm. of mercury at temperature t
W
=
weight of dry sample in gins.
=
t
temperature of water in the jacket surrounding gas
burette in degrees C.
4.3.3.2 Distillation titration method (alternative to the
standard method.)
4.3.3.2.1 Apparatus (see Figure 2).-The apparatus consists
of a heating mantle, a 125 ml. round bottom distilling flask, a
three-way side arm adapter, a 50 ml. burette fitted with a number
5 size rubber stopper, water cooled condenser, adapter, and a 125
ml. Erlenmeyer flask. Standard taper ground glass joints are
used to connect the distilling flask, side-arm adapter, condenser
and adapter. The three way side-arm adapter has a female
joint at its upper end to which the burette is fitted with the
Number 5 rubber stopper. A thin film of silicone grease may
be applied to all of the ground glass joints.
4.3.3.2.2 Solutions
a. Ceric ammonium nitrate, 0.1 Normal (N). This solution
is made up 2N with respect to perchloric acid.
b. Sodium Oxalate, 0.1N. The NBS oxidmetric standard
is used.
c. Perchloric acid, 3N.
4.3.3.2.3 Procedure.-Air dry a portion of the sample as
described in 4.3.3.1.2. Transfer an accurately weighed portion of
from two to three mini-equivalents (0.2911 to 0.4366 gins.) of
the dried sample to a small porcelain (or glass) crucible or
boat. Cover the sample with water. To prevent foaming add a
small amount of Down Corning Anti-Foam AF Emulsion, or equivalent,
to the reaction flask before the introduction of the sample.
Place the sample in the distilling flask, using rubber tipped
forceps. Connect the ground glass joints of the apparatus.
Connect the burette to the three way side-arm adapter by means
of the Number 5 rubber stopper. Transfer an accurately
measured volume of about 40 to 50 ml. of 0.1N eerie ammonium
nitrate to the Erlenmeyer flask in a postion so that the
adapter from the condenser extends below the surface of the eerie
ammonium nitrate. Fill the burette with 3N perchloric acid.
Caution shall be exercised when adding perchloric acid to the
distilling flask. Check to assure that all glass joints are sealed,
10
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