化學其他 DSE、CE 選擇題（第 4 頁）

31.

Questions 20 and 21 refer to the following experiment. When carbon and concentrated sulphuric acid are heated together, sulphur dioxide and carbon dioxide are produced. These two gases are then passed through solution X and solution Y as shown below :

Which of the following combinations of solution X and solution Y can be used to show that sulphur dioxide and carbon dioxide are produced ?

	Solution X	Solution Y
	bromine water	calcium hydroxide solution
	iron(II) sulphate solution	calcium hydroxide solution
	acidified potassium dichromate solution	sodium hydroxide solution
	acidified potassium permanganate solution	sodium hydroxide solution

32.

Questions 20 and 21 refer to the following experiment. When carbon and concentrated sulphuric acid are heated together, sulphur dioxide and carbon dioxide are produced. These two gases are then passed through solution X and solution Y as shown below :

Which of the following statements concerning the reaction between carbon and concentrated sulphuric acid are correct ?

(1)The oxidation number of carbon changes from 0 to +4.

(2)The oxidation number of hydrogen in sulphuric acid remains unchanged.

(3)Concentrated sulphuric acid acts both as a dehydrating agent and an oxidising agent.

33.

Which of the following processes would produce sulphur dioxide ?

(1)roasting iron pyrite in air

(2)heating zinc with concentrated sulphuric acid

(3)mixing dilute hydrochloric acid with sodium sulphite

34.

For Questions 28–30, decide whether each of the two statements is true or false. If both are true, decide whether the second correctly explains the first.

A.Both are true and the second correctly explains the first.

B.Both are true but the second does not correctly explain the first.

C.The first is false but the second is true.

D.Both are false.

1st statement	2nd statement
Molten sulphur is a good conductor of electricity.	Sulphur molecules are mobile in molten sulphur.

35.

For Questions 28–30, decide whether each of the two statements is true or false. If both are true, decide whether the second correctly explains the first.

A.Both are true and the second correctly explains the first.

B.Both are true but the second does not correctly explain the first.

C.The first is false but the second is true.

D.Both are false.

1st statement	2nd statement
Isotopes of an element have the same mass.	Isotopes of an element have the same number of protons.

36.

For Questions 28–30, decide whether each of the two statements is true or false. If both are true, decide whether the second correctly explains the first.

A.Both are true and the second correctly explains the first.

B.Both are true but the second does not correctly explain the first.

C.The first is false but the second is true.

D.Both are false.

1st statement	2nd statement
Carbon can form a large number of compounds with long carbon chains.	Carbon atoms can share electrons with one another.

37.

Which of the following mixtures can produce chlorine ?

38.

For Questions 48–50, decide whether each of the two statements is true or false. If both are true, decide whether the second correctly explains the first.

A.Both are true and the second correctly explains the first.

B.Both are true but the second does not correctly explain the first.

C.The first is false but the second is true.

D.Both are false.

1st statement	2nd statement
Galvanised iron is used for making food cans.	Zinc can prevent iron from rusting by sacrificial protection.

39.

For Questions 48–50, decide whether each of the two statements is true or false. If both are true, decide whether the second correctly explains the first.

A.Both are true and the second correctly explains the first.

B.Both are true but the second does not correctly explain the first.

C.The first is false but the second is true.

D.Both are false.

1st statement	2nd statement
Cracking is an endothermic reaction.	Cracking results in an increase of number of molecules.

40.

For Questions 48–50, decide whether each of the two statements is true or false. If both are true, decide whether the second correctly explains the first.

A.Both are true and the second correctly explains the first.

B.Both are true but the second does not correctly explain the first.

C.The first is false but the second is true.

D.Both are false.

1st statement	2nd statement
Soapy detergent can be used to treat oil spillage on sea surface.	Soapy detergent can act as an emulsifying agent for oil.