adding script tag in head of specific pages

A simple google search can help you do this, well same question was answered before, you can see the answer here.

Use WordPress methods in your functions.php to do this :

function load_scripts() {
    global $post;
    wp_register_script( 'home', get_template_directory_uri() . '/js/home.js', array('jquery'));
    wp_register_script( 'about', get_template_directory_uri() . '/js/about.js', array('jquery'));
    wp_register_script( 'somepost', get_template_directory_uri() . '/js/somepost.js', array('jquery'));

    if( is_page() || is_single() )
    {
        switch($post->post_name) 
        {
            case 'home':
                wp_enqueue_script('home');
                break;
            case 'about':
                wp_enqueue_script('about');
                break;
            case 'some-post':
                wp_enqueue_script('somepost');
                break;
        }
    } 
}

add_action('wp_enqueue_scripts', 'load_scripts');