Chromate(1-), [N-[8-[[5-[(ethylamino)sulfonyl]-2-hydroxyphenyl]azo]-7-hydroxy-1-naphthalenyl]acetamidato(2-)][methyl [8-[[5-[(ethylamino)sulfonyl]-2-hydroxyphenyl]azo]-7-hydroxy-1-naphthalenyl]carbamato(2-)]-, sodium