2,7-Naphthalenedisulfonic acid, 4-hydroxy-, disodium salt 20349-39-7 4-Hydroxy-2,7-naphthalenedisulfonic acid disodium salt AI3-28534 Disodium 4-hydroxynaphthalene-2,7-disulphonate EINECS 243-754-8 NSC 163929