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# NECO GCE CHEMISTRY PRACTICAL QUESTIONS AND ANSWER EXPO – NOV/DEC 2017

NECO GCE Nov/Dec 2017 Chemistry practical Questions and Answer Expo 1ai) Methyl Orange
Reason:- Titration of strong acid against base
1aii) Yellow
1aiii)Hydrochloricacid
1aiv)2HCL(aq)+ x2Co3 -> 2 x CLaq + H20(aq) + CO2(g)
1b) Molar mass of HcL = 1+35.5
=36.5gmol^-1
Con of A is moldm^-3 =
Con of A of gdm^3/molar mass in gdm^3
=7.30gdm^-3/36.5gmol^-1
=0.200moldm^-3
(1bii)
CaVa/CbVb=na/nb
Ca=0.200mol/dm^3
Va=26.20cm^3
Cb=?
Vb=25.0cm^3
na=2
nb=1
(0.200*26.20)/(Cb*25.0)=2/1
Cb=(0.200*26.20*1)/(25.0*1)
Cb=5.24/36.5
Cb=0.2098mol/dm^3
(1biii)
Conc. of B in gdm-3/Conc. of B in moldm-3
=10.6gdm-3/0.148 gdm-3
=101.15g
=101gmol-1
(1biv)
Relative atomic mass of X
2x+12+17.8=101
2x=101-29.8
2x=71.2
x=35.6
========================
(2ai)
INFERENCE: Sample X is a soluble salt
(2aii)
OBSERVATION: A gas is evolved. The gas turns red moist litmus blue.
INFERENCE: Alkaline gas
(2aiii)
INFERENCE: CO3 gas is CO3^2-
(2aiv)
INFERENCE: The solution is alkaline
======================
3b)
– Burrette
– Reshort Hand
– Solution/Acid