In which one of the following arrangements the given sequence is not strictly according to the properties indicated against it?

1. Acidic character of hydrides (${\text{NH}}_3$ to ${\text{SbH}}_3$) increases due to decrease in bond strength. Correct.2. Oxidizing power of dioxides increases down Group 14 due to the inert pair effect ($+4$ to $+2$). Correct.3. Acidic strength increases from $\text{HF}$ to $\text{HI}$. Correct.4. Incorrect sequence: Down the group (${\text{H}}_2\text{O}$ to ${\text{H}}_2\text{Te}$), the acidic strength increases. This means the $K_a$ increases, and thus $p{K}_a$ ($-\log K_a$) must decrease.Order for $p{K}_a$: ${\text{H}}_2\text{O}>{\text{H}}_2\text{S}>{\text{H}}_2\text{Se}>{\text{H}}_2\text{Te}$.