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NECO Chemistry Practical 2021 Questions and Answers . Free 2021 NECO June/July (Bio) (Practical) Chemistry practical specimen questions and answers released by the National examination council. In this article, we are going to be talking about the the answers to the upcoming practical in Chemistry For you to have good NECO result in Physics examination, you are required to pass the NECO practical physics examination.

NECO CHEMISTRY PRACTICAL 2021

Wednesday 14th July, 2021

10:00am – 12:45pm

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Practical – Chemistry – 10:00am–12:00noon

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2021 NECO CHEMISTRY PRACTICAL ANSWER

(1a)
Tabulate

Volume of pipette used=25cm3.
Indicator used= Methyl orange

Under Titration, Rough, 1st, 2nd, 3rd,

Final burette reading; |25.00| |23.40| |23.50| 23.60|

Initial burette reading; |0.00| |0.00| |0.00| |0.00|

Volume of A used; |25.00| |23.40| |23.50| |23.60|

(1ai)
Average volume of Acid used=23.40+23.50+23.60/3 =70.5/3=23.50cm3

(1aii)
This is because it is a reaction between a weak acid and strong base

(1aiii)
A funnel should be used while transferring the acid into the burette.

(1bi)
Conc of A in mol|dm³ =?
Conc of A in g|dm³ = 12.75g|dm³
Molar mass of A, NaHSO⁴ = 23+1+32+64
=120g|dm³

From.
Conc(mol/dm³) = conc(g/dm³)/molar mass

Conc =12.75/120
Conc =0.106mol/dm³

(1bii)
Con of B in mol/dm³ =?
Ca =0.106, Cb =? Va =23.50cm³, Vb =25.00cm³

na=1 , nb=1
From; CaVa/CbVb=na/nb
Cb=CaVanb/Vbna
Cb=0.10623501/25.001
Cb=2.5/25
Cb=0.1mol/dm³

(1biii)
Conc of B in g/dm³=?
Molar mass of B , NaOH=23+16+1=40g/mol
From; conc(g/dm³)=conc(mol/dm³)molar mass
=0.140
=4.0g/dm³

(1biv)
Mass of salt formed =?
Recall mole of NaHSO⁴=?
From; mole =con(mol/dm³)*vol(cm³)/1000

Mole=0.106*23.50/1000
Mole=0.0025mol of NaHSO⁴

By proportion 1mol of NaHSO⁴ produce 1mol of Na²SO⁴ 0.0025mol of NaHSO⁴ will produce X mol of Na²SO⁴ X=0.00251=0.0025mol of NaSO⁴
Molar mass of Na²SO⁴=(232) + 32 + (16*4)
=46+32+64
=142g/mol

Recall; mole =mole/molar mass
Mass =mole * molar mass
Mass =0.0025*142
Mass =0.36g of Na²SO⁴

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(2a)

[PLEASE PUT IN A TABULAR FORM]

TEST
C + 5cm³ of distilled water

OBSERVATION
It dissolve completely

INTERFERENCE
C is a soluble salt

(2bi)
TEST
Solution + NaOH + Heat

OBSERVATION
Effervescence occurs in which a colourless gas with pungent smell and turns red litmus paper to blue is given off.

INFERENCES
NH³ gas from NH⁴+ is present

(2bii)
TEST
Stirring rod of HCL + gas given off

OBSERVATION
a gas which gives a pop sound is given off

INFERENCES
H² is present

(2ci)
TEST
Solution C + drops of BaCL²

OBSERVATION
a white precipitate is formed

INFERENCES
CO²^-3, SO²^-4, SO²^-3, May be present.

(2cii)
TEST
Solution in C(i) + dil HCL

OBSERVATION
the white precipitate dissolve is dil HCL and effervescence occurs in which a colourless and odourless gas which turns blue litmus red and lime water milky is given off

INTERFERENCE
CO² gas from CO²^3- confirmed

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(3a)
(i)Ca²+
(ii)Pb²+

(3bi)
concentrated acid can be defined as an acid formed when a large quantity of an acid dissolve in a small or little volume of water.

(3bii)
A strong acid is defined as a type of acid that ionize completely in a solution

(3c)
Activated charcoal is used as an adsorbent material

(3d)
(i)Reddish – Brown
(ii) I – red, II – brown.

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CHEMISTRY PRACTICAL SPECIMEN 2021: