Ch. 15 Acids HKCEE 97II(31). Which of the following statements concerning citric acid is/are correct? 1. It is a strong acid. 2. It is present in oranges. 3. It exists as a solid at room temperature. A. B. C. D.
1 only 2 only 1 and 3 only 2 and 3 only
D 01I(2a) State an expected observation and write a chemical equation for the reaction involved. Adding dilute hydrochloric acid to zinc granules 2HCl + Zn ZnCl2 + H2 (1M) Zinc dissolves in acid to give a colorless solution./Colourless gas bubbles evolved.(1M) Ch.16 Alkalis 95II(49) Statement 1. If a student accidentally spills some hydrochloric acid on his hand, he should immediately wash his hand with sodium hydroxide solution. Statement 2 Sodium hydroxide solution can neutralize hydrochloric acid. C. Only one statement is true while the other is false. 98I(6ai1) A student prepared sodium nitrate solution by reacting 1M sodium hydroxide solution with dilute nitric acid. Write the chemical equation for the reaction. (An ionic equation will NOT be accepted for this question.) HNO3(aq) + NaOH(aq) NaNO3(aq) + H2O(l) 98II(12) In which of the following combinations would X react with Y? X Y A. ammonia potassium iodide B. chlorine potassium nitrate C. carbon dioxide sodium hydroxide D. sulphur dioxide iron(II) sulphate C
99I(8aiii) Suggest a chemical test to show the presence of ammonium ions in the moist paste of ammonium chloride. (3M) Warm the paste with NaOH(aq) (1) Evolution of a gas (ammonia) (1) which turns moist pH paper (red litmus) blue (1)/ gives white fumes with HCl(g) indicates the presence of NH4+ NH4Cl(aq) + NaOH(aq) NH3(g) + H2O(l) + NaCl(aq) 01I(2b) For each of the following experiments, state an expected observation and write a chemical equation for the reaction involved: Adding sodium hydroxide solution to iron(II) sulphate solution. (2M) NaOH + FeSO4 Na2SO4 + Fe(OH)2 (1M) Green precipitate will formed/ The green colour of the solution becomes paler (colourless). (1M) 03I(8bi) Write the ionic equation for the following reaction. (25.0 cm3 of 0.503 M sodium hydroxide solution was added to 25.0 cm3 of the nickel(II) sulphate solution to precipitate out nickel(II) hydroxide.) 2OH- + Ni2+ Ni(OH)2
(1m)
95II(7) Which of the following substances, when mixed, would undergo a chemical reaction? A. copper and zinc sulphate solution B. calcium chloride solution and magnesium nitrate solution C. lead(II) nitrate solution and sodium hydroxide solution D. bromine water and sodium chloride solution C 99II(20) Which of the following solutions would produce a white precipitate with sodium hydroxide solution? A. B. C. D.
lead(II) nitrate solution iron(III) nitrate solution copper(II) nitrate solution potassium nitrate solution
A 01II(11) Which of the following pairs of solutions, when mixed, would produce a precipitate? A. lead(II) nitrate and sodium hydroxide B. copper(II) sulphate and sodium nitrate C. zinc chloride and potassium nitrate D. iron(II) sulphate and acidified potassium permanganate
A 97II(37) Which of the following substances would react with sodium hydroxide solution? 1. ammonium chloride solution 2. copper(II) sulphate solution 3. ethanoic acid A. B. C. D.
1 and 2 only 1 and 3 only 2 and 3 only 1, 2 and 3
D 97II(15) Which of the following substances, when mixed, would produce a precipitate? A. chlorine water and potassium bromide solution B. ethyl ethanote and ethanol C. iron(III) sulphate solution and aqueous ammonia D. nitric acid and potassium hydroxide solution C 98II(25) Dilute sodium hydroxide solution is added successively to four different solutions. Which of the following combinations is correct? Solution Observation A. ammonium chloride white precipitate B. lead(II) nitrate yellow precipitate C. potassium dichromate orange precipitate D. iron(II) sulphate brown precipitate D 02II(17) Which of the following solutions does NOT react with sodium hydroxide solution? A. ammonium chloride solution B. potassium carbonate solution C. copper(II) nitrate solution D. zinc sulphate solution B Ch.17 Indicators and pH 97I(3b) Arrange the following substances in the order of increasing pH and explain your answer. (1M ethanoic acid , 1M hydrochloric acid, 1M sulphuric acid)
pH: 1M sulphuric acid < 1M hydrochloric acid <1M ethanoic acid (1) ethanoic acid is a weak acid which undergoes incomplete ionization, so it has the highest pH value (or both hydrochloric acid and sulphuric acid are strong acids/ undergo complete ionization.) (1) sulphuric acid is dibasic while hydrochloric acid is monobasic, so 1M H2SO4
contains a higher concentration of H+(aq) ions than 1M HCl
(1)
98II(9) Which of the following substances has a pH less than 7? A. lemon juice B. soap solution C. glass cleaner D. milk of magnesia A 02II(5) Consider the aqueous solutions listed below: 1. 1M ethanoic acid 2. 1M hydrochloric acid 3. 1M ammonia solution Which of the following represents the increasing order of pH of the solutions? A. 1, 2, 3 B. 2, 1, 3 C. 3, 1, 2 D. 3, 2, 1 B 97I(3a) Suggest ONE method to determine the pH of an aqueous solution. Using pH paper/ universal indicator/ pH meter
(1)
Ch.18 Strength of Acids and Alkalis 03II(45) Statement 1: Sodium hydroxide is an active ingredient in anti-acid tablets. Statement 2: Sodium hydroxide is a strong alkali. A (Both statements are correct. Statement 2 is an explanation for statement 1.)