WordPress has a generic handler to deal with all forms – admin-post.php.

If you include a hidden field in your form called action, you can then hook in to a function of your choice with all the goodness of wordpress included.

echo "<form action='".get_admin_url()."admin-post.php' method='post'>";
echo "<input type='hidden' name='action' value='submit-form' />";
echo "<input type='hidden' name='hide' value='$ques' />";
{ Enter the rest of your first block of code from above here }

And then in your functions.php file (or any other php file that you have included via functions.php), you can use this method.

add_action('admin_post_submit-form', '_handle_form_action'); // If the user is logged in
add_action('admin_post_nopriv_submit-form', '_handle_form_action'); // If the user in not logged in
function _handle_form_action(){

    { Enter your second block of code from above here }