Anomalous Behaviour of Fluorine

Q. The variation of the boiling points of the hydrogen halides is in the order $HF>HI>HBr>HCl$
What explains the higher boiling point of hydrogen fluoride?

1. There is strong hydrogen bonding between HF molecules.
2. The bond energy of HF molecules is greater than in other hydrogen halides.
3. The effect of nuclear shielding is much reduced in fluorine which polarises the HF molecule.
4. The electronegativity of fluorine is much higher than for other elements in the group.

Q. Mark the incorrect statement(s):

1. The bond dissociation enthalpy of $F_2$ is greater than that of $C{l}_2$
2. The boiling point of $HX$ (where $X$ is a halogen) increases uniformly down the group
3. The solubility of iodine in water increases greatly in the presence of $I^{-}$ ion
4. $N_3^{–}$ is a pseudo halide

Q. Fluoride can form polyfluorides $F_3^{-}$ - True or False?

1. True
2. False

Q. Stability decreases in the order

1. H-F > H-Cl > H-Br > H-I
2. H-Cl > H-F > H-Br > H-I
3. H-F > H-Br > H-Cl > H-I
4. H-F > H-Cl > H-I > H-Br

Q. Acidity increases in the order

1. H-F > H-Cl > H-Br < H-I
2. H-F < H-Cl < H-Br < H-I
3. H-F > H-Cl > H-Br > H-I
4. H-F > H-Cl < H-Br > H-I

Q. Fluoride can form polyfluorides $F_3^{-}$ - True or False?

1. True
2. False