During the reaction of some metal with dil. HCl acid following observations were made

1. The temp of the reaction mixture rises when Al is added
2. The reaction Na metal is found to be highly explosive
3. Some bubbles of a gas are seen when Pb is reacted with acid

Explain these explanations .

1. The temperature of the reaction mixture rises when aluminium is added because it is an exothermic reaction.
2. Reaction of sodium metal is found to be highly explosive because it is an exothermic reaction
3. When lead is treated with hydrochloric acid, bubbles of hydrogen gas are evolved 
   
   Pb + 2HCl → PbCl2 + H2

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