1. In the first reaction, a metal is being reacted with an acid where is in second reaction a base is being reacted with an acid.2. In first reaction hydrogen gas is being evolved where as in second reaction water is released.3. In first reaction, 2 moles of acid is reacting where is in 2nd reaction only one mole of acid is reacting.4. Second reaction is also a neutralization reaction where is in first reaction there is no neutralization reaction.