KCSE CHEMISTRY QUESTIONS AND ANSWERS PER TOPIC
(a) describes one method that can be used to distinguish between sodium sulphate and sodium hydrogen sulphate.
b) Describe how a pure sample of lead (II) sulphate can be prepared in the laboratory starting with lead metal c) Study the flow chart below and answer the questions that follow:
i) Write an equation for the reaction in:
I step II; II step IV ii) State the observation made in step III. Explain. iii) Name another substance that can be used in step V.
ANSWERS
​(a)Test the acidity using a litmus pager. There will be no change on litmus when dipped into a solution of sodium sulphate . The litmus paper turns to red when dipped into a solution of sodium hydrogen sulphate .
OR Add a solid carbonate to each solution. No effervescence observed when the carbonate is added to a solution of sodium sulphate. Effervescence is observed when the carbonate is added to a solution of sodium hydrogen sulphate. (b)Add dilute nitric acid to lead to form a soluble salt, Pb(NO3)2, add a soluble salt, Na2SO4. Then dry the salt between filter papers . (c)(i) NH4 NO3 → N2O + 2H2O II 2Fe(OH)3(S) → Fe2O3(s) + 3H2O(l) (ii) The colour changes from pale green to brown . The iron (II) is oxidised to iron (III) chloride by hydrogen peroxide (iii) Carbon monoxide ​Related Chemistry Questions and Answers on Nitrogen and It's Compound Form 3 Level
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