Caustic soda (sodium hydroxide tiah auhmi zong a si) cu a phunphun in hman khawhmi le tam deuh in hmanmi riantuannak chemical a si i, cu hna cu thilpuan, vun le cauk, alumina, savun le thil sawhnak, petroleum thianhnak le ti thianhnak tibantuk riantuannak phunphun ah hmanmi a si. A tlangpi in a sining pahnih in zuar a si: ti (alkali) le fek (flakes). Caustic soda flakes cu lam hlapi ah phurh a fawi deuh i ramdang kuatnak caah duh deuhmi thilri a si. Mah company cu India ram ah caustic soda chuahtu nganbik pahnihnak a si i kum khat ah ton 1 million chuah khawhnak a ngei.