1, BASICLABORATORYTECHNIQUES.
1. TEST TUBE
Test tubes are used for conducting various tests with small amount of reagents Test
tubes of different sizes are available .Small test tubes (called semimicro test tubes) are
used for salt analysis. Test tubes like boiling tubes and centrifiuging tubes are also avaiable
2. BEAKER
Beakers are used for mixing, holding, boiling and transferring various liquids .Beakers
are of different sizes such as 150 ml,250 ml,500 ml etc. made of soft glass and corning
glass are available.
3. FUNNEL
Funnel is used for transfering liquids and for filtration It is acone shaped wide glass tube
ended in to along narrow neck. Glass or polythene funnels having different diameters
are available for different operations in the laboratory.
4. WASH BOTTLES
The wash bottle is a convenient water container used for rinsing apparatus, washing
precipitates , makingup of solution etc. For this purpose either a glass wash bottle or a
polythene wash bottle can be used.
i Glass Wash Bottle: The glass wash bottle consists of (a) a flat bottomedglass flask,
(b) a long glass tube (30cm) bend at 5cm from one end to an angle of 600,(c)a short
glastube (15cm) bend at the middle to an angle of 1200,()aglass jettube (S cm). (e)
a piece of rubber tube for connecting the jet tube, () the longer glass tube and (g) a
suitable two-holed rubber cork (stopper) fortheflask.
These parts are assembled and fitted into the flask as shown in the diagram.
Middie rone
Hotest purion
Barrol
(Burner tube)
Alr holc
-Arregulator
Pin hole
D-Side tube
Basc
TEST T
Test tul
tubes
used fe
250 ml
2. BEA
Beal
are
gla
Funnel
Test Tube
3. FU
Beaker
F
e
Jet Tube
Short Glass
Tube
Rubber Tube
Jet Tube
4.
Long Glass
Tube
Rubber cork --
Washer
Flask
Lid
Tube
Bottle
Parts of glass wash bottle
Water
Polythene wash bottle with water
Glass wash bottle with
wate
Test for airtightness : The stoper is removcd with its fittings .About halfthe
the flask is filled with water randthe stopperis replaced. The outer end ofthe
is finly closed with thetip ofa finger and air is blown into theflask through
.The waterlevel inthe longertube rises above the water level and remains the
vshoonluemre
je,it
shows that the bottle is air-tight.
s
t
e
a
d
y
wash
t
.Waterrises the longer tube and discharges through thejet..
s
h
ot
e
r
iü. Polythene Wash bottle: The polythene wash bottle consists of an elongated
bottle
that
screwed.The lid
its
through
polythene tube can be inserted air-tight by
whi
c
h
a
l
o
n,
The
above the lid and
tube isbe
the bottle and the connectedI with apolythene jettube at its outer end. Wateriis
with tube screwed air-tight on to bottle.
f
i
l
e
d
i
n
By
bottle ,water
brought tthrough the jettube.
pr
e
ssi
n
ghe
THE BUNSEN
BURNER
How to use the
in
with alid
5.
bottle. Air is blown into the bottle thrOugh the
can be :
is
lid
can be
has a hole in centre
tby means ofapolythene washer.
its
iis
the
out
The bunsen
burner is used for heating3purposes .Petrol gas or LPG mixedi
used as the fuel.
with air is
Partsof the bunsen burner:The
burmer, the barrel(bumer tube) and theBunsen burner consists of the base .nipple of the
air regulator.
0. Base :Base is
made of cast
side tube called 'the gas tube`iron It keeps the burner in astable upright
for the entry ofthe gas and
position.It hasa
can be connected
through arubber tube.
to the gas tap
ii. Nipple of the
burner : It is made of brass rod and has a
Atits
lower end,the nipple is screwed into
fine pin-hole runing
the base .The gas
throughit.
enters the base through the gas
coming
from
the
gas holders
tube and passes through the
pressure.
nipple of the burner under
ii, The Barrel
tube): It is ametallic tube with
lower end.The(Burner
gas
two
from the air holes. passing out the nipple enters into the opposite air holes near its
burner tube and mixes with air
iv.
:This is a
Airregulator
tube .It is pierced with smal metallic ring that loosely fits on
the lower end of the
two holes that
burner tube.It can be rotated
exactly
burner
to the two air
to
correspond
holes of the
wholly closing the air holes. regulate supply of air into the
burner tube by partialy or
Howto ight the
The air holes are
the gasescapesburner:
tely closed. When the gas tapis
the nipple,there iscompl
affalleof
sucked inthroughthrough
the air holes .On
and
pressure
a result of opened
as
lighting ,the gas burns with a
vwhich air is
The air rgultor is then ajustexd until ablue non-luminoUs flame is obtained.
Non-luminous flamet Anon-uminous flnme is ustunlly used for heating lt consists of
three zones.
The dark blue inner ozone of unbunt gas
-Mar
20
Conlcal Fsk
Stoppor
Nole
Mrk
Plpette
48
20
Noler
cOck
Burette
Measuring Cylinder
iüThe pale blue middle ozone (reducing region) of partially bunt gas and.
üi.The nearly colourless outer ozone (oxidising region) of completely burnt gas .The
hotest portion of theflame, about 1600 Kis near the foot ofthe oxidising region.
6. CONICAL FLASK
Conicial flask is used in volumetric titrations and filtrations It has flat
bottom.
7. MEASURING CYLINDER
where high
The measuring cylinder is used to measure out adefinite volume ofaliquid
gradu
precisions is not needed.It is auniformglass cylinder withaflattened base .It is
is marked
ated in cm or in ml begining from the bottom. The total volume ofthecylinder
cm,500 cm (ml) etc.are
onthetop.Measuring cylinders with capacities of 10cm,100
in availabe.
stopper. Athin line etched
9.
aroundthe neck indicates the volume that it
can
particular
tempenture.
Standard
flasks
with
capacitics
of
100
cm'
(
ml),
250
are in
commonuse.
PIPETTE
hold
The pippette is
to withdrawa definite volume ofa liquid from one
intended
transfer it into another.It consistssofa cylindrical bulb joined at both ends tovessel
the: andy
tubing.The lower (delivery) tube is drawn out to a finetip(nozzle).A mark is
nar gwe
around the upper (suction) into the volume ofthe pipute uptothe mark is indicatedetchea
onte
Bulb.
10.BURETTE
t1sa long graduated glass tube of uniformbore fused with a glass stop -cock and.
nozzle at the lower end. The burette is graduated in ml
or cm3 from top to
bottom.The
graduation begins from zero at the top and proceeds downwards to fifty at the botom
Each ml or cm' is sub-divided into tenequal parts. Each small division thus corespoNds
to 0.1 ml or 0.lcm².