Question

Which of the following is/are true statement(s)?

• A. The basic nature of $X^{-}$ is in the order $F^{-}>C{l}^{-}>B{r}^{-}>I^{-}$
• B. $HI$ is the strongest acid among $HF,HCl,HBr\text{and}HI$
• C. The ionic character of $M-X$ bond decreases in the order $M-F>M-Cl>M-Br>M-I$
• D. Fluorine does not form any oxoacids

Answer 1

Answer: (A), (B), (C)

The correct options are
A The basic nature of $X^{-}$ is in the order $F^{-}>C{l}^{-}>B{r}^{-}>I^{-}$
B $HI$ is the strongest acid among $HF,HCl,HBr\text{and}HI$
C The ionic character of $M-X$ bond decreases in the order $M-F>M-Cl>M-Br>M-I$

$\left(a\right)$ &$\left(b\right)$: The order of acidic strength of $HX$ is $HI>HBr>HCl>HF$ i.e. $HI$ is strongest acid as its bond dissociation energy is lowest due to large size of iodine. Also stronger the acid weaker its conjugate base so order of basic nature is $F^{-}>C{l}^{-}>B{r}^{-}>I^{-}$

$\left(c\right)$ Ionic charater depends upon the electronegativity difference between the cation and the anion in a compound. Since Fluorine has the highest electronegativity, $H-F$ will be more ionic than the other $H-X$'s and as the electronegativity decreases down the groupp, the ionic nature of $H-X$ also decreases down the group.

$\left(d\right)$ $F$ does form an oxoacid $HOF$