Wordpress - Determine if page is the Posts Page

is_home() checks for the "Posts Page", despite the somewhat confusing function name.

Wordpress comes with 7 primary template page types, which can be determined on this way

if ( is_main_query() ) {
    // Error
    if ( is_404() ) {
        ;
    }
    // Front page
    if ( is_front_page() ) {
        ;
    }
    // Archive
    if ( is_archive() ) {
        ;
    }
    // Comments popup
    if ( is_comments_popup() ) {
        ;
    }
    // Search
    if ( is_search() ) {
        ;
    }
    // Singular
    if ( is_singular() ) {
        ;
    }
    // Home - the blog page
    if ( is_home() ) {
        ;
    }
}

is_home tells to you, that you have the blog page.