In binary acids, acidity increases as you go down a column due to increasing atomic size and bond distance.

In binary acids, acidity increases as you go down a column due to increasing atomic size and bond distance.

• A. True
• B. False
• C. Only for halogens
• D. Only for noble gases

Answer: (A)

Acidity in binary acids rises as you move down the group because the bond between hydrogen and the nonmetal gets weaker and the conjugate base becomes more stable. As the halogen gets larger, the H–X bond lengthens and its bond dissociation energy decreases, so it breaks more readily in water to release H+. At the same time, the resulting X− ion is larger and more polarizable, which allows the negative charge to be spread over a bigger volume, stabilizing the anion and favoring dissociation. That combination—weaker H–X bonds and more stable conjugate bases—makes the acids stronger down the column. In practice, HF is a weak acid, while HCl, HBr, and HI are progressively stronger, with HI typically the strongest among them. Noble gases don’t form typical binary acids in water, so the trend doesn’t apply there.

Acidity in binary acids rises as you move down the group because the bond between hydrogen and the nonmetal gets weaker and the conjugate base becomes more stable. As the halogen gets larger, the H–X bond lengthens and its bond dissociation energy decreases, so it breaks more readily in water to release H+. At the same time, the resulting X− ion is larger and more polarizable, which allows the negative charge to be spread over a bigger volume, stabilizing the anion and favoring dissociation. That combination—weaker H–X bonds and more stable conjugate bases—makes the acids stronger down the column. In practice, HF is a weak acid, while HCl, HBr, and HI are progressively stronger, with HI typically the strongest among them. Noble gases don’t form typical binary acids in water, so the trend doesn’t apply there.