NECO-GCE-CHEMISTRY-PRACTICAL-ANSWERS

(3ai)
CO2 can be removed by adding caustic soda i.e sodium hydroxide
(3aii)
Purity of water can be determined through it’s boiling point as it’s noted that pure water boils at 100°c
(3aiii)
AgNo3 produce brown fumes as NO2 is produced on heating
(3aiv)
It changes blue litmus paper red as the hydrogen ion in the wet litmus forms as acid on exposure to the litmus paper
(3bi)
Diagram

(3bii)
It cannot be collected by displacement of air be cause nitrogen constitutes to large percentage of the air constituents (78%)
(3biii)
HCL gas or ammonia gas (pick one)
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2a)
C is soluble salt
2ai)
Zn^2+ or Al^3+ present

-Zn^2+ or Al^3+ present
2aii)
Zn^2+ or Al^3+ present

-Zn^2+ is confrim
2bi)
SO3^2- or SO4^2-present
2bii)
SO3^2- present
2biii)
SO3^2- confrim
2c)
ZnSO3
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1ai)
Tabulate
Titration|1|2|3|
Final burette reading (cm^3) |21.30|
21.50|24.00|
Initial burette reading (cm^3) |01.30|01.00|03.50|
1aii)
average volume of acid used
= 1st+2nd+3rd/3
=20.50+20.50+20.50/3
=61.50/3=20.50cm^3
1aiii)
Volume reading are when the reading are exactly the same
1aiv)
Because it is a reaction between strong acid and strong base
1av)
i)Avoid air bubbles in the pipette
ii)rinse the pipette with the base solution before use
1avi)
the base sodium hydroxide has a soapy feel
1bi)
mole= 0.6mol1dm^3*20.50cm^3/1000
=1.23/1000=0.00123mole
1bii)
conc in mol1dm^3
=4.0/40=0.1mol1dm^3
1biii)
mole =0.1mol1dm^3*25cm^3/1000
=2.5/1000=0.0025mole
1biv)
mole of acid = 0.00123mole m 0.001mole
mole of base= 0.0025mole m 0.003mole
mole ratio =0.001/0.003=1:3
1ci)
it is a strong acid.
Methly orange is used as an indicator in a strong acid, strong base titration
1cii)
H3PO4+3NaOH—>Ha3PO4+3H2O
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Completed
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