Q1: Zinc nitrate reacts with aqueous ammonia (NH4OH) to form a salt and a base. (i) Name the salt and the base. (ii) Describe the observations for the reaction. (iii) Write a chemical equation for the reaction (include state symbols). (iv) Write an ionic equation for the reaction.

(i) Salt: Ammonium nitrate
Base: Zinc hydroxide

(ii)A white precipitate of zinc hydroxide Zn(OH)2 is formed.

(iii)

(iv)

Q2 Ammonium sulfate is heated with sodium hydroxide. (i) Write a chemical equation (include state symbols) for the reaction. (ii) Describe a test for the gas.

(i)

(ii) Turns damn red litmus paper blue

Q3 An unknown green solution is heated with a piece of aluminium foil and sodium hydroxide solution. (i) The gas produced turns damp red litmus paper blue. Name the gas evolved. (ii) This is a confirmatory test for an anion. Name this anion. (iii) Give a possible cation which gives the green solution.

(ii)Nitrate


(iii)Iron (II), Fe2 +

Q4 Sulfuric acid is titrated with potassium hydroxide in the preparation of potassium sulfate salt. (i) Explain why this method is recommended for the preparation for this salt. (ii) Write an ionic equation for the reaction.

(i)Titration is use to prepare Group(I) salt. (soluble salt)

(ii)

Q5 Excess zinc carbonate is added to hydrochloric acid in the preparation of zinc chloride salt. (i) Write an ionic equation for the reaction. (ii) Why excess zinc carbonate is used? (iii) Briefly explain how the zinc chloride crystals can be obtained.

(i)

(ii) To ensure that all the hydrochloric acid is completely reacted with the zinc carbonate.

(iii)

Step 1: Add excess zinc carbonate solid to beaker of dilute hydrochloric acid until there is excess white zinc carbonate solid left behind.
Step 2: Filter to remove the excess unreacted zinc carbonate solid.
Step 3: Evaporate the zinc chloride solution to remove water and make a saturated salt solution.
Step 4: The hot saturated solution form zinc chloride salt when it is cooled.