Weakest NaH < H₂S < H₂Te < HI strongest
NaH is a strong base, it is not acid at all, it ionized to give Na⁺ and H⁻
From up to bottom in periodic table size increases so dissociation of H⁺ becomes easier for larger anions so HI and H₂Te are stronger acids than H₂S
I is more electronegative than Te, So it is easier to lose H⁺ from I than from Te
