New NECO Chemistry Practical Specimen 2021 - NECO Chemistry Practical Questions and Answers (Updated)

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Table of Contents

NECO Chemistry Practical Specimen 2021

These are the recent 2021 NECO Chemistry Specimen;

NECO Chemistry Specimen 2021

TITRATION
(i) Dilute sodium hydroxide solution
(ii) Dilute ammonia solution
(iii) Dilute hydrochloric acid
(iv) Dilute trioxonitrate(V)acid
(v) Distilled water
(vi) Red and blue litmus paper
(vii) Barium chloride solution
(viii) Phenolphthalein solution
(ix) Methyl orange
(x) One boiling tube
(xi) Five test tubes
(xii) Source of heat
(xiii) Wash bottle containing distilled water
(xiv) Filtration apparatu

NECO Chemistry Practical Questions and Answers (Updated)

Note that the above are the practical Specimen for NECO Chemistry Practical and not answers to any questions. Here is the answers while the exams will comense.

2021 NECO Chemistry Answers Updated

(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

===========================

(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