Chem HKCEE 5題

14. Which of the following solutions can react with bromine water to give a
colourless solution ?
A. sodium chloride solution
B. sodium sulphite solution
C. sodium iodide solution
D. sodium hypochlorite solution

22. A white solid dissolves in water to give an alkaline solution. The solution
reacts with dilute hydrochloric acid to give a gas. The solid is probably
A. calcium oxide.
B. calcium carbonate.
C. potassium hydroxide.
D. potassium carbonate.

34. Which of the following statements concerning helium is/are correct ?
(1) The outermost electron shell of a helium atom has an octet
structure.
(2) Helium is used to fill weather balloons.
(3) Helium exists as monatomic molecules. [只要解釋(1)和(2)]
A. (1) only
B. (2) only
C. (1) and (3) only
D. (2) and (3) only

42. Which of the following statements concerning carbon, silicon and
phosphorus are correct ?
(1) Carbon forms numerous compounds with hydrogen and oxygen.
(2) Silicon is used to make computer chips.
(3) Phosphorus is an essential element for plant growth. [只要解釋(1)]
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)

44. Which of the following statements concerning sulphur dioxide are correct ?
(1) It can be prepared by heating copper turnings with concentrated
sulphuric acid.
(2) It is denser than air.
(3) It can be absorbed by sodium hydroxide solution. [只要解釋(1)和(3)]
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)

請解釋點解岩同唔岩~~thank you