Chemistry Practical. Alternative A verified questions and answer

(1)
TABULATE:
Volume of pipette
Burette reading(cm3)@Rough titre(cm3)@1st titre
(cm3)@2nd titre(cm3)
Final reading(cm3) @20.00@19.60@19.60
Initial reading(cm3)@0.00 @0.00 @0.00
Volume of acid used @20.00@19.60@19.60
Average titre=(19.60+19.60)/2 cm3
=39.20/2 cm3
=19.60cm3
Equation=>2MnO4^-+5C2O4^2-+16H^+-
>2NA^2++8H2O+10CO2
(1bi)
Conc of B in mol/dm3
CaVa/CbVb=Na/Nb
(0.05*19.6)/(Cb*25.0)=5/2
5*Cb*25=2*0.05*19.6
Cb=(2*0.05*19.6)/(5*25)=1.96
Cb=0.0157mol/dm3
Cb=0.016mol/dm3
(1bii)
Conc in B in g/dm3
=0.0157*158
=2.4806g/dm3
=2.481g/dm3
2)
I) TEST A = C + distilled H20
OBSERVATION = Partly soluble colorless filtrate white
residue
INFRENCE = C is mixture of soluble & insoluble salts
--------------------------------------------------------------------
II) TEST B = Filtrate + AgNo3 , | HNO3 , | excess NH3
OBSERVATION = White PPT | PPT Insoluble | PPT
dissolve
INFRENCE = Cl^- , SO3^2-, CO3^2- present | Cl- presnt |
Cl- confirmed
---------------------------------------------------------------------
III) TEST = Residue + HNO3
OBSERVATION = Effervescence colorless,odorless gas,
turns lime water milky.
INFRENCE = CO2(g) , CO3^2- is present
--------------------------------------------------------------------
Iv) TEST = Filtrate + NaOH in drop
OBSERVATION = White Gelatinous PPT
INFRENCE = -----
--------------------------------------------------------------------
IV)(ii) TEST = Filtrate + NaOH in Excess
OBSERVATION = PPT dissolve
INFRENCE = Zn2+ , Pb2+ present
--------------------------------------------------------------------
IV)(iii) TEST = Filtrate + NH3 in drop
OBSERVATION = White Gelatinous PPT
INFRENCE =
---------------------------------------------------------------------
IV)(iv) TEST = Filtrate + NH3 in Excess
OBSERVATION = PPT Dissolve
INFRENCE = Zn2+ confirmed
(3a) The differences in Boiling point of a liquid is
(I) they are used to separate the mixture of
color
(II) with close different boiling point
(3b) (i) To make the accurate result of the
solution
(II) To avoid the error of decimal
3c)
C1=2.5moldm³
V2=500cm³
Ç2=0.2moldm³
V1=?
C1V1=C2V2
V1=C2V2/C1
V1=0.2*500/2.5
V1=40.0cm³.
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