Question

(a) The list below shows some chemical processes.

        chlorination                  chromatography                       cracking

                            crystallisation                            decomposition

          electrolysis                fractional distillation                  polymerisation

Identify the process from the list that is used:
(i) in the treatment of drinking water

……………………………………………………………………………………………………………………. 

(ii) to separate a mixture of dyes

…………………………………………………………………………………………………………………….

(iii) to extract aluminium from bauxite

……………………………………………………………………………………………………………………. 

(iv) to produce long chain molecules from monomer units.

…………………………………………………………………………………………………………………….

(b) When dilute hydrochloric acid is added to aqueous sodium hydroxide, a neutralisation reaction occurs.
Fig. 2.1 shows apparatus used to investigate the change in pH as the acid is added.

(i) State the name of apparatus A.

……………………………………………………………………………………………………………………. 
(ii) State the reading on the pH meter when the dilute hydrochloric acid exactly neutralises

the aqueous sodium hydroxide.
……………………………………………………………………………………………………………………. 

(iii) State the two products of the reaction shown in Fig. 2.1.

1 ……………………………………………………………………………………………………………………….
2 ……………………………………………………………………………………………………………………….
(c) Describe what is observed when aqueous sodium hydroxide is added to blue copper(II) sulfate  solution.
…………………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………………… 

▶️Answer/Explanation

Ans:  2(a)(i) chlorination ; 
2(a)(ii) chromatography ; 
2(a)(iii) electrolysis ; 
2(a)(iv) polymerisation ; 
2(b)(i) burette ; 
2(b)(ii) 7 ; 
2(b)(iii) sodium chloride ;

water ;

2(c) pale blue precipitate ;