NECO Chemistry Practical 2024 | Questions & Solutions

This post is about NECO Chemistry Practical 2024. We are making the post to help candidates who are finding it difficult to answer NECO Chemistry practical questions. So if you are one of such candidates, ensure that you read through this article. We will show you the best and easy ways to answer NECO Practical Chemistry Alternative A and B questions. You can make a good grade in your Chemistry examination if you pay attention to the formats we will give you here.

Before attempting to answer questions in NECO Chemistry Practicals, it is very important that you understand the  making scheme. The reason is so that you can present your answers in such a way that they meet the requirements. That’s the only guarantee that you will get the full marks allotted to each question you attempt.

Bear in mind that every single procedure is awarded marks. So, ensure you do not skip any step while reporting and presenting your practical results.

The Chemistry Practical question paper will consist of two sections and general Chemistry questions, namely:

1. Quantitative Analysis
2. Qualitative Analysis

These involve titration and test of ions. You will carry out an experiment and report your inference and observation. What you will see will not be far from the NECO Chemistry Specimen given to your school.

Note: Your Chemistry teacher will give you your titration endpoint. It is not the same for every school but within a range.

Do not use the endpoint here. It may vary from your center endpoint but you can follow the calculation procedures.

NECO Chemistry Practical 2024 Specimen

Below is the 2024 NECO Chemistry Practical specimen…

Requirements:

(a) One burette (50cm³)

(b) One pippete (20cm³/25cm³). However, all candidates in a center must use pipettes of the same volume.

(c) The usual apparatus and reagents for qualitative work including:
(i) Dilute sodium hydroxide solution
(ii) Dil. ammonia solution
(iii) Dilute hydrochloric acid
(iv) Barium chloride solution
(v) Distilled water
(vi) Red and Blue litmus paper
(vii) Phenolphtalein

(d) Methyl orange

(e) One boiling tube

(f) Five test tubes

(g) Filtration apparatus

(h) Source of heat

NECO Chemistry Practical 2024 Specimen for Qualitative Analysis

Each candidate should be supplied with the following: with Labels An, Bn, Cn, where ‘n’ is the candidate’s serial number.

(a) 150cm³ of chloride acid solution in a bottle with label “An”. The acid solution which should be the same for all candidates will contain 3.4cm³ of the concentrated hydrochloric acid per dm³ solution.

(b) 150cm³ of sodium hydroxide solution in a bottle with label “Bn”. The solution which should be the same for all candidates will contain 4.0g of sodium hydroxide per dm³ of solution.

(c) One spatulaful of copper (ii) tetraoxosulphate (vi) salt in a specimen bottle labelled “Cn”.

NECO Chemistry Practical 2024 Practice Questions

The questions below are strictly for practice and not NECO Chemistry Practical 2024 expo.

All your burette readings (initials and final) as well as the size of your pipette must be recorded but no account of experimented procedure is required. All calculations must be done in your booklet.

Question 1

A is O.200 moldm³ of HCI. C is a solution containing 14/3_g of Na₂CO₃. x H₂O in 500 cm³ of solution.

(a) Put A into the burette and titrate it against 20.0 cm³ or 25.0 cm³ portions of C using methyl orange as indicator. Repeat the titration to obtain Consistent titre values. Tabulate your results and calculate the average volume of A used. The equation for the reaction is: Na₂CO₃ x H₂O + 2HCL_(aq) → 2NaCI_(aq) + CO2_(g) + (x+1) H₂O_(I).

(b) From your results and the information provided. Calculate the:
(i) concentration of C in moldm^-3;
(ii) concentration of C in gdm^-3;
(iii) molar mass of Na₂CO₃, xH₂O;
(iv) the value of x in Na₂CO₃ xH2O. [H = 1.0; C=12.0; O = 16.0; Na =23.0]

Credit will be given for strict adherence to the instruction, for observations precisely recorded and for accurate inferences. All tests, observations and influences must be clearly entered in the booklet in ink at the same time they are made.

Question 2

F is a mixture to two inorganic salts. Carry out the following exercise on F. Record your observation and identify any gas(s) evolved. State the conclusions you draw from the result of each test.

(a) Put all of F in a beaker and add about 10cm³ of distilled water. Stir well and filter. Keep the filtrate and the residue.

(b) (i) To about 2cm³ of the filtrate, add NaOH_(aq) in drops and then in excess (ii) To another 2cm³ portion of the solution, add a few drops of NHO_3(aq) followed by few drops of AgNO_3(aq).

(c)(i) Put all the residue into a clean test-tube and add NHO_3(aq) followed by few solution from 2(d)(i) add NaOH_(aq) in drops and then in excess.

Question 3

State what would be observed if the following reactions are carried out in the laboratory:
(i) methyl orange is dropped into a solution of lime juice
(ii) hydrogen sulphide gas is bubbled through iron (III) chloride solution;
(iii) sulphur (IV) oxide gas is bubbled into acidified solution of KMnO4;
(iv) ethanoic acid is added to a solution of K₂CO₃.

NECO Chemistry Practical 2024 Answers to Practice Questions

1. Indicator                                 =          Methyl Orange

Volume of the base used        =          25.00cm³

Titration	Rough Titre	1st Titre	2nd Titre	3rd Titre
Final Burette readings cm3	24.70	24.80	24.70	24.90
Initial Burette reading cm3	0.00	0.00	0.00	0.00
Volume of acid used cm3	24.70	24.80	24.90	24.90

Average Titre              =          1^st + 2^nd + 3^rd/3

=          24.80 + 24.70 + 24.90/3

=          24.80cm³

Alternatively, we can use 2 concordant titres to calculate average titre.

Equation of the reaction: Na₂CO₃ XH₂O + 2HCI_(aq) → 2NacI_(aq) + CO_2(aq) + (x+1)H₂O_(I)

C_AV_A/C_BV_B     =  n_A/n_B

C_A = Molar concentration of HCI_(aq) in moldm³

V_A = Volume of acid used in cm³ = 24.80cm³

C_B = Molar concentration of Na₂Cu₃ xH₂O in moldm³

n_A = 2; n_B = 1

(b) (i) concentration of C in moldm^-3 = ? From the equation of reaction:

C_AV_A/C_BV_B     =  n_A/n_B

C_A = 0.200 moldm³     V_A = 24.80cm³

C_B = ?                          V_B = 25.00cm³

Now Substite known values into the equation

0.200 x 24.80/ C_B x 25.00 = 2/1

C_B = 1×0.200×24.80/2×25.00

C_B­ = 0.0992 moldm^-3

(ii) Concentration of C in g dm^-3 = ?

500cm² → 14.3 g

1000cm3 →14.3/500 x 1000² g

= 28.6 g dm^-3

(iii) Molar mass of Na₂CO₃ xH₂O

Molar conc in moldm^-3 = conc in g dm^-3 / molar mass

Therefore: Molar mass g mol^-1 = conc in g dm^-3 / molar conc in moldm^-3

= 28.6 g dm^-3/0.0992 moldm^-3

= 288.3065

Approximately 288 g mol^-1

(iv) Value of x in Na₂CO₃ xH₂O?

[H = 1.0, C = 12.0, O = 16.0, Na = 23.0]

Na₂CO₃ xH₂O = 288

2(23) + 12 + 3 (16) + x (2(I) + 16) = 288

46 + 12 + 48 + 18x  = 288

106 + 18x  = 288

18x   = 288 – 106

18x      = 182

x       = 182/18

x       = 10.11

x approximately 10

Table of Observations, Inferences and Conclusions from Question 2

2	Test	Observation	Inference
(a)	F + distil water + stir + filter	Effervescence (bubbling) occurs. Colourless and odourless gas evolve after filtration pale blue/colourless filtrate and green residue
(b)(i)	Filtrate + NaOH(aq) in drops then in excess	White precipitate formed. Precipitate insoluble in excess NaOH(aq)	Ca2+/Pb2+   Ca2+ present

(b)(ii)	Filtrate + NH3(aq) in drops then in excess	No visible reaction   No visible reaction OR	Ca2+ present   Ca2+ confirmed
(b)(i)	Fil trate + NaOH(aq) in drops then in excess	Blue gelatinous precipitate formed   Precipitate insoluble in excess	Cu2+  is present
(b)(ii)	Filtrate + NH3(aq) in drops then in excess	Pale (light) blue gelatinous precipitate formed   Precipitate dissolves to form a deep blue solution	Cu2+     Cu2+  is confirmed
(c)	Filtrate + NHO3(aq) + AgNO3(aq)	No visible reaction No gas involved White precipitate formed	CuI-  is present
(d)(i)	Residue + HNO3(aq)	Effervescence occurs, colourless and odourless gas evolves that turns blue litmus paper to red and turns lime water milky	CO2(g) CO32- present
(d)(ii)	Solution from 2(d)(i) + NaOH(aq) in drops then in excess	Blue precipitate formed   Precipitate insoluble in excess NaOH(aq)	Cu2+    Cu2+   present

3 (a)(i) Solution of lime juice turns to pink or red.
(ii) The FeCI₃ solution changes colour from brown to green and a yellow deposit.
(iii) The purple colour of the KMnO₄ solution turns colorless or decolorised.
(iv) T he solution of K₂CO₃ reacts with the addition of ethanoic acid to evolve a colorless, odorless gas with bubbling of effervescence.

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