Page 224 - Chemistry ICSE Class IX
P. 224
212 ICSE Chemistry – 9
'ZRGTKOGPV Observations Inference
/'4%74; ++ 1:+&'
Observe the salt and its colour. Orange-red, heavy amorphous It is a salt of Pb(II) or Hg(II).
powder.
Heat the given salt and identify On heating,
the gases evolved. y it turns dark red and nally to May be a Hg(II) salt.
black.
y colourless and odourless gas The evolved gas may be oxygen.
is given out, which ignites a
glowing wooden splinter.
y silvery globules (small Silvery globules are of OGTEWT[.
droplets) are formed near the
mouth of the test tube. This
deposit appears as a mirror. 6JG IKXGP UCNV KU /GTEWT[ ++
oxide.
heat
Reaction: 2HgO(s) o 2Hg(l) + O (g)
2
mercury(II) oxide mercury oxygen
(silvery globules)
.'#& +8 1:+&'
Observe the salt and its colour. Chocolate-brown heavy May be a salt of lead.
amorphous powder
Heat the given salt and identify On heating strongly, it
the gases evolved. y changes to reddish-brown
colour.
y gives off colourless and odour- Evolved gas is oxygen.
less gas, which ignites glowing
wooden splinter to ames.
Examine the residue. When hot, the residue is reddish- 4GUKFWG KU NGCF ++ QZKFG 2D1
brown, which changes to yellow
on cooling.
It fuses into glass and stains the 6JG IKXGP UCNV KU NGCF +8 QZKFG
test tube yellow. 2D1
2
heat
Reaction: 2PbO (s) o 2PbO(s) + O (g)
2
2
lead(IV) oxide lead(II) oxide oxygen
64+.'#& 6'64#1:+&' 4'& .'#&
Observe the salt and its colour. Red/orange-red heavy May be a salt of lead.
amorphous powder
Heat the salt and identify the On heating, its colour changes to May be a salt of lead.
gases evolved. reddish-brown
On strong heating, Evolved gas is oxygen.
y it gives off a colourless and
odourless gas which ignites a
glowing wooden splinter into
ame.
Examine the residue. When hot, the residue is reddish- Residue may be PbO.
brown, which changes to yellow
on cooling.
It fuses into glass and stains the The given salt is trilead
test tube yellow. VGVTCQZKFG 2D O
3 4
