Consider the following pairs: I. Pigment : TiO2 II. Drier : Turpentine III. Thinner : Naphthenates IV. Antiskinning agent : Polyhydroxy phenol. How many of the pairs given above are correctly matched?

In paint chemistry: TiO2 (titanium dioxide) is the most common white pigment — pair I is correct. Driers are metal salts of organic acids such as naphthenates (cobalt/manganese naphthenate), not turpentine — pair II is wrong. Turpentine is actually used as a thinner; naphthenates are driers — pair III is also wrong. Antiskinning agents like polyhydroxy phenols (e.g., guaiacol, butylated hydroxytoluene) prevent skin formation in stored paint — pair IV is correct. So two pairs (I and IV) are correct.