Exam Name: Chemistry Practical
Course: Secondary Level
TAKABA BOYS’ SECONDARY SCHOOL
FORM IV ENTRANCE EXAMINATIONS NOVEMBER 2010
KENYA CERTIFICATE OF SECONDARY EDUCATION
Time: 1 hr
You are provided with:
• Solution A, dilute hydrochloric acid .
• Solution B 0.25M sodium hydroxide solution.
(i) Pipette 25.0cm3 of solution B into a conical flask.
Add 3 drops of phenolphthalein indicator. Titrate with dilute hydrochloric acid, solution A from the burette. Repeat until you obtain three concurrent readings. Record your results in the table below.
Table Burette readings
1st 2nd 3rd
Final Burette reading
Initial burette reading
Volume of solution A, used (cm3)
ii) Calculate the:
I average volume of solution A used. (1mk)
II Number of moles of sodium hydroxide, solution B contained in 25.0cm3 of 0.25M NaOH. (1mk)
III Write the equation of reaction between sodium hydroxide and the hydrochloric acid. (1mk)
IV The moles of the hydrochloric acid (solution A) reacting hence its molarity (2mks)
2. a) You are provided with solid Q. Carry out the tests below and write your observations and inferences in the spaces provided.
(i) Heat half of solid Q in a clean dry test tube, test the gases produced with both blue and red litmus paper.
(ii) Using a boiling tube, dissolve the rest of solid Q in about 10cm3 of water
I. To about 2cm3 of the solution in (ii) above, add aqueous ammonia solution drop wise until in excess
II . To about 2cm3 of the solution, add 3 drops of sodium chloride solution.
III. Warm the mixture in II above.
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