where to insert <appSettings... > tag in web.confid file

dear sir,
i am unable to short out a problem that i get when inserting this <appSettings....> code in web.config file.i think i am not placing it right place..so plz help

Code:

<appSettings>
    <add key="SQLCON" value="Data Source=.\sqlexpress;Initial Catalog=DB1;Integrated Security=True;Pooling=False"/>
  </appSettings>

after inserting this in web.config i am properly writing the SqlConnection statements in main .cs file.