Final answer:
Binary acid strength increases as you go right across a period on the periodic table due to increased electronegativity and bond polarity.
Step-by-step explanation:
Binary acid strength increases as you move right across a period on the periodic table. As the electronegativity of the element (E) to which hydrogen is bonded increases within a period, the E-H bond becomes more polar. This polarization favors dissociation to form H+ and the more stable conjugate base, thus increasing acid strength.
A clear example of increasing acid strength across a period is observed with the binary hydrides of the second row of the periodic table, where the order of increasing acidity is CH4 < NH3 < H2O < HF, reflecting an increase in electronegativity from carbon to fluorine.
Similarly, among binary hydrides, as we move down a group on the periodic table, the acid strength increases due to a decrease in bond energy, caused by a weaker overlap between hydrogen's 1s orbital and the valence orbital of the larger atom. For instance, within Group 16, the acid strength increases as follows: H2O < H2S < H2Se < H2Te.