Tranquilizers are neurologically active drugs. These affect the message transfer mechanism from nerve to receptor. Common tranquilizers are: Diazepam (Valium), Chlordiazepoxide (Librium), and Alprazolam (Xanax). An antacid is a drug/substance which neutralizes stomach acidity. Examples: Equate (mixture of CaCO3, Al(OH)3 and Mg(OH)2), Omeparazole, etc.
Hence, Valium, Librium and Alprazolam are used as tranquilizers.