化學 1992 年 DSE、CE 選擇題（第 4 頁）

31.

Which of the following reagents can be used to distinguish between Fe²⁺(aq) and Fe³⁺(aq) ions ?

(1)ammonia solution

(2)concentrated nitric acid

(3)acidified potassium permanganate solution

32.

Which of the following reagents form(s) a white precipitate with lead(II) nitrate solution?

(1)potassium carbonate solution

(2)dilute hydrochloric acid

(3)sodium sulphate solution

33.

Which of the following aqueous solutions, when electrolyzed using carbon electrodes, will liberate only gaseous products at both electrodes ?

(1)KOH(aq)

(2)AgNO₃(aq)

(3)MgCl₂(aq)

34.

Which of the following statements concerning the reaction between dry chlorine and hot iron wire is/are correct ?

(1)Iron(II) chloride is formed.

(2)A solid product is obtained after cooling to room temperature.

(3)Chlorine is reduced.

35.

Which of the following can be used to distinguish between dilute hydrochloric acid and dilute nitric acid ?

(1)copper

(2)silver nitrate solution

(3)sodium hydrogencarbonate solution

36.

A compound, C₂H₄O₂, react with ethanol in the presence of concentrated sulphuric acid to form a product with a fruity smell.

Which of the following statements about this compound is/are correct ?

(1)It can liberate carbon dioxide from sodium carbonate solution.

(2)It can decolourize acidified potassium permanganate solution.

(3)Its aqueous solution is an electrolyte.

37.

Which of the following polymers is/are NOT suitable for making a container for boiling water?

(1)perspex

(2)urea-methanal

(3)polyvinyl chloride

38.

For each of the following questions, 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 statements are true and the 2nd statement is a correct explanation of the 1st statement.

B.Both statements are true but the 2nd statement is NOT a correct explanation of the 1st statement.

C.The 1st statement is false but the 2nd statement is true.

D.Both statements are false.

1st statement	2nd statement
Polyester is a thermoplastic.	Polyester is formed by condensation polymerization.

39.

For each of the following questions, 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 statements are true and the 2nd statement is a correct explanation of the 1st statement.

B.Both statements are true but the 2nd statement is NOT a correct explanation of the 1st statement.

C.The 1st statement is false but the 2nd statement is true.

D.Both statements are false.

1st statement	2nd statement
In the reaction between calcium carbonate and hydrochloric acid, the reaction rate decreases with time.	The molar concentration of hydrochloric acid decreases as the reaction between calcium carbonate and hydrochloric acid proceeds.

40.

For each of the following questions, 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 statements are true and the 2nd statement is a correct explanation of the 1st statement.

B.Both statements are true but the 2nd statement is NOT a correct explanation of the 1st statement.

C.The 1st statement is false but the 2nd statement is true.

D.Both statements are false.

1st statement	2nd statement
A solution of hydrogen chloride in methylbenzene can turn blue litmus paper red.	Hydrogen chloride dissolves in methylbenzene to form hydrogen ions.