Page 222 - Chemistry ICSE Class IX
P. 222
210 ICSE Chemistry – 9
'ZRGTKOGPV Observations Inference
Result: The given salt is hydrated zinc nitrate.
Gas evolved contains: Water vapour, Nitrogen dioxide and Oxygen.
Residue left behind: Zinc oxide (ZnO)
'
.
Reaction: Zn(NO ) 6H O o Zn(NO ) + 6H O
3 2
3
2
2
zinc nitrate hydrate zinc nitrate (anhydrous) water
heat strongly
2Zn(NO ) o 2ZnO(s) + 4NO (g) + O (g)
2
3 2
2
zinc nitrate zinc oxide nitrogen dioxide oxygen
(reddish-brown)
4. AMMONIUM CHLORIDE
Observe the salt and its colour White crystalline solid with It may be a compound of
ammoniacal odour. ammonia.
Heat the salt and identify the gas On heating, it sublimes forming It may be ammonium chloride.
evolved dense white fumes.
The gas evolved is ammoniacal
and irritating.
The white fumes on cooling
form white powdery mass on the
cooler part of the test tube.
Residue, if any No residue is left behind. The given substance/salt is
COOQPKWO EJNQTKFG
'
Reaction: NH Cl(s) o NH (g) + HCl(g)
3
4
ammonium chloride ammonia hydrogen chloride
.'#& ++ 0+64#6'
Observe the salt and its colour Heavy, white crystalline solid. May be a salt of lead.
Heat the salt and identify the gas On strong heating, it crumbles May be a salt of lead.
evolved with a crackling noise.
Reddish-brown gas evolves. It The evolved gas is nitrogen
turns moist blue litmus paper red. dioxide.
When a glowing wooden splinter The evolved gas is a OKZVWTG QH
is held in the reddish-brown gas, NO and O .
2
2
it starts burning with ame.
The residue is reddish-brown Residue is NGCF ++ QZKFG.
when hot. On cooling, it changes
to yellow.
Examine the residue The yellow residue appear partly 6JG IKXGP UCNV KU NGCF ++ PKVTCVG
fused into glass.
'
Reaction: 2Pb(NO ) (s) o 2PbO(s) + 4NO (g) + O (g)
2
3 2
2
lead(II) nitrate lead(II) oxide nitrogen dioxide oxygen
EXPERIMENT 2.2
Objective
To study the action of heat on some coloured substances/salts
