The diagram shows a screwdriver being used as a lever to open a tin

(a) Most reactive       Metal B

                                   Metal D

                                   Metal A

Least reactive           Metal C

(b) (i) Bubbles should form very slowly

(ii) No reaction takes place

Explanation:

(a) The given metals arranged in their order of reactivity are;

Most reactive       Metal B

                              Metal D

                              Metal A

Least reactive      Metal C

The other of reactivity is based on the nature of their reactivity of the metals in air

(b) (i) Based on the reactivity of the metals in air, whereby metal A reacts very slowly and an oxide is formed, we have that, based on the reactivity of the metal A, when mixed with dilute hydrochloric acid, bubbles should form very slowly

(ii) Similarly, given that metal C is unreactive, we have that when small pieces of metal C are added to dilute hydrochloric acid, no reaction takes place.

graph slopes whilst gas cools, then it is flat whilst conensation to liquid happens, the coolong liquid then graphs as a slope when it solidifies graph is flat

latent heat