Silicon ͑100͒ wafers, predipped in 1:20 ͑v/v͒ HF water, were treated separately with four different acid mixtures, viz., HNO 3 , H 2 SO 4 -H 2 O 2 , HNO 3 -HF, and H 2 SO 4 -H 2 O 2 -HF, for different time durations. Subsequent vigorous rinsing with deionized water rendered the wafer surfaces with hydroxyl termination. Synthesized surfaces were characterized by diffuse-reflectance infrared Fourier transform spectroscopy ͑DRIFTS͒, ellipsometry, contact angle and atomic force microscopy. Surfaces treated with HNO 3 and H 2 SO 4 -H 2 O 2 showed increasing hydrophilicity at room temperature due to the formation of silanol ͑−SiOH͒ terminated chemical oxides, with continuous oxide growth. An increase in hydrophilicity was observed during the first 15 min of treatment with HNO 3 -HF and H 2 SO 4 -H 2 O 2 -HF acid mixtures, causing a decrease in the hydrophilic character with longer incubation times. DRIFTS analysis confirmed the addition of HF in the oxidizing acid mixture controls chemical oxide proliferation, through creating a surface with mixed −SiOH and silicon hydride ͑−SiH x ͒ termination. Prolonged incubation in acidic mixtures containing HF resulted in a logarithmic increase of −SiH x coverage, rendering the surface hydrophobic. Incubation for 15 minutes in each of the four acid mixture systems generated surfaces with comparable hydrophilicity, controlled oxide growth and reduced surface roughness.