(i) Silver is a very less reactive metal (as it placed below hydrogen in reactivity series). Thus, it does not react withdil. HCl.
(ii) The reaction of Al with dil. HCl is exothermic, i.e. heat is produced in the reaction, hence the temperature of the reaction mixture rises.
(iii) Sodium is a very reactive metal. It reacts vigorously with the evolution of heat too.
(iv) Bubbles are seen due to the evolution of H2 gas.
(v) CO2 gas is produced when Na2C03 reacts with dil. HCl.
