difference between generic error and standard detailed error

hi,
while writing the code when we use like
Catch(Exception ex)
{
   throw new Exception(ex.Exception)
}
i.e called as the generic exception
but when we use the specific execption like
catch (ArithmeticException ex)
{
  throw new Exception(ex.Exception)
}
this is called the standard Error, i hope you got it.

Generic means it will take care of any kind of Execption.