This question was  extremely difficult for the candidates. They could not provide 
the expected responses to the various parts of the question. The required 
responses to the various parts are given below. 
                      (a)  (i & ii)
                      
                        A hydrometer
                      (b) (i) 1.240 - Half charged
 (i i) 1.098 - Discharged
(iii) 1.265  - Fully charged 
                      (c) (i) The flammable gas is hydrogen. 
  (ii) The  components are casing, terminals, separators, plates. fine  caps  and sediment traps or bridge