(i) Caustic soda : It is the commercial name of NaOH. It is used : (a) in refining of petroleum. (b) in the manufacture of soap, paper, rayon, drugs and dyes. (ii) Sodium Carbonate : It is used : (a) in laundries and in softening of water as washing soda. (b) in the manufacture of glass, sodium silicate, paper, borax, caustic soda, etc. (iii) Quick lime : It is used : (a) in the purification of sugar, manufacture of dye stuffs, bleaching powder, $CaC_2$, mortar, cement, glass, etc. (b) as a cheap alkali, i.e., as acid neutraliser.