NECO Chemistry Practical Questions and Answers 2023/2024 (Complete Solution)

NECO Chemistry Practical 2023. Many NECO candidates find it difficult to answer the NECO Practical Chemistry Alternative A and B correctly due to not understanding the questions. I will show you the best way to answer the 2023 NECO Chemistry Practical questions and make a good grade in your Chemistry examination.

It is pertinent you understand the NECO Chemistry Practical making scheme before attempting any questions so as to present your answers in such a way that it will look attractive to the examiner to earn you big marks.

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 be expected to 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 titration endpoint will be given to you by your Chemistry teacher. 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.

See:

• NECO Timetable
• How to Check NECO Result

NECO Practical Chemistry Questions and Answers (Expo)

Note: The 2023 NECO Chemistry Practical answers will be posted here today 13th July during the NECO Practical Chemistry exam. Keep checking and reloading this page to know when the answers are posted. Do not forget to reload this page in order to see the answers.

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Today’s Chemistry Practical Answers:

For question 1

Use your school’s endpoint (average titre value). Ours is 21.20cm³. Wherever you see our endpoint (21.20cm³), put ur school’s own. Your Chemistry teacher should have given you people before now…and calculate with ur school endpoint.

Replace our 21.20 in 1bi and re-do the calculation with ur own titre value u placed there.

If your school wants to use mine, then the chemistry teacher must submit endpoint similar to ours without much difference…eg 21.15, 21.20, 21.20, 21.30, 21.40, etc

The answer you got in 1bi, use it to solve 1bii.
Example: we calculated 0.04 x 21.20 / 25.00 and got 0.03392 but if u replaced our 21.20 with ur school’s endpoint, u won’t get same 0.03392 with us.

Then u can see we used 0.03392 we got in 1bi to solve in 1bii and used the answer we got to solve 1biii. So when u replace, remember to re-calculate in all.

You are a science student, you should definitely understand what I meant.

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NECO Chemistry Specimen Practice Questions

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) Dilute 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
Each candidate should be supplied with the
following: Labelled An, Bn, Cn, where ‘n’ is the
candidate’s serial number.
(a) 150cm³ of chloride acid solution in a bottle
labelled “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 labelled “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”.

The questions below are strictly for practice not the 2021 Chemistry 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.

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.

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). (d)(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.

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.

CHEMISTRY PRACTICALS ANSWERS

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 2 concordant titres can be used 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

Substitution of known values

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

            18x      = 182

               x       = 182/18

               x       = 10.11

               x approximately 10

2	Test	Observation	Inference
(a)	F + distil water + stir + filter	Effervescence (bubbling) occurs, colourless and odourless gas evolved 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)	Filtrate + 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 colourless or decolourised. (iv) The solution of K₂CO₃ reacts with the addition of ethanoic acid to evolve a colourless, odourless gas with bubbling of effervescence.

If you have any questions about the 2021 NECO Chemistry Practical questions and answers, kindly let us know in the comment box.

Last Updated on July 13, 2023 by Admin