Question Library

(a) Write an equation for the reaction of chlorine with (i) potassium iodide solution; (ii) zinc on heating (b) Identify the product Q in the following reaction: Cl\(_2\) + 2NaOH \(\to\) NaCl + H\(_2\)O + Q.

(a) List two uses of sodium trioxocarbonate (IV). (b) Sodium trioxocarbonate (IV) solution is alkaline. (i) What phenomenon is responsible for this observation? (ii) Name the product obtained on passing carbon (IV) oxide into saturated sodium trioxocarbonate (IV) solution.

Xg of a pure sample of iron (II) sulphide reacted completely with excess dilute hydrochloric acid to give 3.20g of iron (II) chloride according to the following equation: FeS\(_{(s)}\) + 2HCI\(_{(aq)}\) ---> FeCl\(_{2(aq)}\) + H\(_2\)S\(_{(g)}\). (a) Mention one method apart from heating by which the reaction can be made to proceed faster (b) Calculate the value of X. [CI = 35.5, Fe = 56; FeS = 88g mol\(^{-1}\)]

(a) If a steel spoon were to be plated with silver, state what would be suitable for use as the; (i) anode. (ii) cathode; (iii) electrolyte (b)(i) Write an equation for one of the reactions involved in the purification of bauxite. (ii) Give the reason why the carbon anodes are changed at intervals during the electrolysis of pure alumina solution in molten cryolite.

(a)(i) List the quantum number that are assigned to an electron in an atom. (ii) What is the maximum number of electrons that can occupy the 3d orbital? (b) An element represented as P has the following electronic configuration: 1s\(^2\)2s\(^2\)2p\(^6\)2s\(^2\) (i) Write the electronic configuration of the ion of P. (ii) Without identifying P, write the likely formula of its chloride. (iii) State with reason, whether P will be a good oxidizing or reducing agent. (c)(i) What is electron affinity? (ii) Explain briefly why ammonia can precipitate in dative bonding. (d)(i) If an element in Group IV loses an alpha particle, to which group would the product belong? (ii) Two equally toxic substances X and Y which decay to non-toxic products, were absorbed through the skin. If their half-lives are 8 minutes and 2 months respectively, which of them constitutes the greater health hazard? Explain your answer

(a)(i) What type of reaction is involved in each of the conversion processes indicated as I to V below? (ii) Name one isomer of glucose (iii) Explain why palmwine becomes sour on prolonged exposure to air. (b)(i) List the reagents and the reaction condition necessary for ethanoic acid to form an alkanoate. (ii) Give two uses of alkanoates (c)(i) What is the lUPAC name of the following compound? (ii) Outline one chemical test to distinguish between methane and the compound in (c)(i) above. (iii) Write an equation for the combustion of ethene in excess oxygen.

(a)(i) Define heat of neutralization (ii) Give the reason why copper (II) chloride can be prepared by neutralization, unlike lead (II) chloride. (b)(i) Describe in outline, the manufacture of trioxonitrate (V) acid by the catalytic oxidation of ammonia, giving equations where appropriate. (ii) What are the products obtained when sodium tioxonitrate (V) is heated strongly? (c) When powdered magnesium is heated to redness in a stream of nitrogen, magnesium nitride (Mg\(_3\)N\(_2\)) is formed. (i) Write an equation for the reaction (ii) Hence, calculate the amount (in mole) of magnesium nitride that can be obtained from 3.0g of magnesium [Mg = 24].

(a)(i) What is an electrolyte? (ii) Classify each of the following as strong electrolyte/weak, electrolyte/non-electrolyte. Potassium chloride; sodium ethanoate, aqueous ammonia; cane sugar (b)(i) Write half-cell equations for the reactions in the Daniel cell . (ii) Why is the Daniel cell classified as an electrochemical cell? (iii) Give two other examples of electrochemical cell. (c) Explain the following observations. (i) Graphite conducts electricity, unlike most non-metals (ii) In the electrolysis of copper (II) tetraoxosulphate (VI) solution, the blue colour fades with platinum electrodes while the colour intensity is unaffected with copper electrodes (equations required) (iii) A solution of dry hydrogen chloride in methylbenzene (toluene) does not conduct electricity whereas hydrochloric acid does.

(a) A soluble chloride X reacted with a liquid Y on heating, to give gas Z which turned moist blue litmus paper red and fumed in moist air. (i) Identity Y and Z (ii) Give one chemical test to confirm that X is a chloride (b)(i) State one laboratory use of calcium chloride. (ii) Name one laboratory technique suitable for separating a mixture of iron filings and ammonium chloride without applying heat. (iii) State the action of solutions of the following salts on litmus respectively: K\(_2\)CO\(_3\); NaNO\(_3\), AICl\(_3\), (NH\(_4\))\(_2\)SO\(_4\).

Credit will be given for strict adherence to instructions, for observations precisely recorded, and for accurate inferences. All tests, observations, and inferences must be clearly entered in your answer book, In ink, a the time they are made. C is a mixture of two simple salts. Carry out the following exercises on C. Record your observations and identify any gases evolved. State the conclusion you draw from the result of each test. (a) Add about 10cm\(^3\) of distilled water to all of C in a boiling tube. Shake the mixture and filter: Keep both the filtrate and the residue. (b) Divide the filtrate into two portions. (i) To the first portion, add about 2cm\(^3\) of barium chloride solution, followed by dilute hydrochloric acid in excess. Warm the mixture and identify any gas evolved. (ii) To the second portion, add few drops of acidified potassium tetraoxomanganate (VIl) solution and shake. (C) Put the residue in a test tube and add about 3cm\(^3\) of dilute hydrochloric acid Warm gently and identify any gas evolved. Keep the mixture. (d) Divide the clear solution from (c) above into two portions (i) To the first portion, add sodium hydroxide solution in drops and then in excess. (ii) To the second, add aqueous ammonia in drops and then in excess.

All your burette readings (initial and final), as well as the size of your pipette, must be recorded but no account of experimental procedure is required. All calculations must be done in your answer book. A is a solution containing 14.0gdm\(^{-3}\) of potassium hydrogen tetraoxosulphate (VI). B is a solution of sodium hydroxide. (a) Put A into the burette and titrate with 20.0cm\(^{-3}\) or 25.0 cm\(^{-3}\) portion of B using methyl orange, as Indicator. Record the volume of your pipette. Tabulate your burette readings and calculate the average volume of A used. (b) From your results and the information provided, calculate the: (i) concentration of A in mol dm\(^{3}\) (ii) concentration of B in g dm\(^3\) (iii) volume of A (in dm\(^{-3}\)) that would produce one mole of Sodium tetraoxosulphate (VI) in solution. The equation for the reaction is: 2KHSO\(_{4(aq)}\) + 2NaOH\(_{(aq}\) \(\to\) K\(_2\)SO\(_{4(aq)}\) + NaSO\(_{4(aq)}\) + 2H\(_2\)O\(_{(l)}\) [H = 1; O = 16, Na = 23, KHSO\(_4\) = 136gmol\(^{-2}\)]

Choose the most appropriate option opposite in meaning to the word or phrase underlined. The climate of Nigeria is an enervating one

Read the following passage carefully and answer the questions on it. We have often heard students making wild assertions that the public examining bodies are their worst enemies. Some, in fact, see the officials of these public examining bodies as wicked souls scheming day and night to devise ways of failing them. How correct are these assertions? The facts will speak for themselves. The task of setting an examination paper begins long before the examination day. Indeed. months or years before then, seasoned experts in the-various subjects are given the teaching and examination syllabuses and requested to set questions. These are compiled for subsequent scrutiny. Then a second set of experts is invited to examine the questions critically, make necessary modifications and come up with questions that conform with acceptable standards. The result of this exercise is a set of polished and unambiguous questions that are very fair to those being examined. These questions are then securely stored. The next stage is the registration of candidates This stage involves not just the examining body, but also the candidates, their parents. their teachers. principals and some other members of the public. This is so because apart from the candidate having to fill in the forms. his principal has to endorse them while the parents have to provide the registration fee. Any mistake or inaction on the part of any of these may ruin the candidates chances. If, for instance, the candidate makes a mistake in his choice of subjects or in completing his forms or if the principal does not forward the registration fee at the right time. his chances in the examination may be jeopardized. Next is the conduct of the examination itself. Again. more officials from outside the examining body than from within it are involved. Think of the supervisors. the invigilators, and even the security officials. They are definitely more in number than the staff of the examining body and any one of them could take an action that might result in the failure of candidates. Take the invigilator for instance If he is negligent candidates could swap answer scripts under his very nose; and when this is detected by the markers, as it often is. the results of the candidates may be cancelled. Probably, the most hated person to the candidates is the marker whom they, in their ignorance, regard as a wicked drunkard who delights in failing candidates. What candidates do not realize is that an examiner is trained to score points strictly according to a carefully prepared marking scheme from which he must not deviate it is his constitution. Besides, his work is consistently checked by his team leader and the chief examiner. Should he be discovered to have marked inaccurately, he could be removed. So, contrary to candidates' opinion. the examiner is a seasoned teacher, a careful scorer, a person always on his guard. The final stage comes with the collation of results. This stage is mainly computerized, and computers do not make mistakes. A candidate's results may not be processed if he is involved in a malpractice, has used a wrong examination number or no number at all, or if he fails to write all the papers that make up a subject. So. when a result is withheld, the fault is mostly that of the candidate. How then should we view the activities of the public examining bodies? Definitely, we should view them with understanding, sympathy and appreciation. (a) In one sentence, summarize the writer's purpose in this passage. (b) In two sentences, one for each, state how the actions of the candidate and the invigilator can jeopardize the candidate's chances of success. (c) In three sentences, one for each summarize the steps taken by examining bodies to ensure that candidates are given a fair chance of success.

You have been sent on indefinite suspension for the part you played in a recent disturbance in which valuable school property was damaged. Write a letter to the principal of your school describing the part that you played and apologizing for your involvement.

Write an article for publication in a national newspaper on why you think a woman should be your country's next president.