Which one of the following is most acidic?

Step-by-step solution

As the size of central atom, (order of size O > S > Se > Te ) increases, the H -A (where A= central atom) bond length increases. Thus, the H - A bond dissociation energy decreases. Consequently H ₂ Te gives a proton ( H ⁺ ) more readily. Hence, it is most acidic among the given. H ₂ Te + H ₂ O H ₃ O ⁺+ HTe ⁻