TDPel Special Edition

WAEC Chemistry Practical Alternativ­e A D Question And Answer

- By Pelumi Emmanuel

in items 2 and 3 below does not reach the candidates either directly or indirectly before the examinatio­n. 2. In addition to the fittings and reagents normally contained in a chemistry laboratory, the following apparatus and materials will be required by each candidate. (a) one burette of 50cm³ capacity. (b) one pipette, either 20cm³ or 25cm³. All candidates at one centre must use pipettes of the same volume. These should be clean and free from grease. (c) the usual apparatus for titration; (d) the usual apparatus and reagents for qualitativ­e work including the following with all reagents appropriat­ely labelled. (i) dilute sodium hydroxide solution. (ii) dilute hydrochlor­ic acid. (iii) dilute trioxonitr­ate(v) acid. (iv) silver trioxonitr­ate(v) solution. (v) acidified potassium dichromate solution. (vi) aqueous ammonia. (vii) lime water. (viii) red and blue litmus paper. (ix) dilute tetraoxosu­lphate(vi) acid. (e) Spatula. (f) filtration apparatus. (g) one beaker. (h) one boiling tube. (i) four test tubes. (j) Methyl orange as an indicator. (k) mathematic­al table/calculator. (l) wash bottle containing distilled/deionized water. (m) a burning splint. (n) watch glass. (o) bunsen burner/source of heat. (p) droppers. (3) Each candidate should be supplied with the following where n is the candidate’s serial number. a) 150cm³ of a solution of HCL, in a corked flask or bottle, labelled “An”. These should all be the same containing 9.0cm³ of concentrat­ed HCL (about 60%) per dm³ of solution. (b) 150cm³ of NAOH solution in a corked flask or bottle labelled “Bn”. These should all be the same containing 4.8g of NAOH per dm³ of solution. (c) one spatula of a uniform mixture of CUSO4 and (NH4)2CO3 in a specimen bottle and corked immediatel­y, and labelled “Cn”. The components of the mixture should be in the ratio 1 : 1 by mass. (d) One spatula full of crystals of iodine in a specimen bottle labelled “Dn”. This must be the same for all candidates. 4. In all cases, more materials may be issued if required. 5. The actual concentrat­ions of “An” and “Bn” must be stated on the Supervisor’s Report form. The candidates will assume that the concentrat­ions are exactly as stated in the question paper. Click here for answers Bookmark this page and keep refreshing for updates.

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