How do metals react with dilute acids ? Explain with the help of an example.

When a metal reacts with dilute acid, salts are formed. During this reaction hydrogen gas is evolved. In other words, when a metal is added to dilute acids, salt and hydrogen gas are formed.
Process
Sulfate salts and chloride salts are formed when metals react with dilute sulfuric acid and hydrochloric acid. Some metals reacts vigorously with dilute sulfuric acid or hydrochloric acid for example, potassium, sodium, lithium and calcium.

$2Na\left(s\right)+2dil.HCl\left(aq\right)\to 2NaCl\left(aq\right)+H_2\left(g\right)$