When two different halogens react with each other, interhalogen compounds are formed. They can be assigned general compositions as \(XX'\), \(XX'_3\), \(XX'_5\) and \(XX'_7\), where \(X\) is a halogen of larger size and \(X'\) of smaller size and \(X\) is more electropositive than \(X'\). As the ratio between radii of \(X\) and \(X'\) increases, the number of atoms per molecule also increases.
On the basis of above passage, answer the questions
Properties of inter halogen compounds are:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → They are co-valent compounds
Interhalogen compounds are formed between two halogens. The electronegativity difference between two halogens is not large enough for electron transfer, so they share electrons: all interhalogens are covalent molecules. All their electrons are paired, so they are diamagnetic in nature. They are volatile solids or liquids at 298 K, except ClF, which is a gas.
Why the other options are incorrect
Option (2) They are paramagnetic in nature — Incorrect. Interhalogens have no unpaired electrons (each XX′n has an even number of electrons, all paired), so they are diamagnetic.
Option (3) They are ionic compounds — Incorrect. Halogens of similar electronegativity share electrons; they do not form ions.
Option (4) They are ferromagnetic in nature — Incorrect. Ferromagnetism is an extreme form of paramagnetism shown by solids such as Fe, Co and Ni with many unpaired electrons in aligned domains; covalent diamagnetic molecules cannot show it.
Note: This question is from the pre-rationalised NCERT book (2022-23). The topic is not there in the latest NCERT book (2026-27), and it is also out of the CUET 2026 syllabus.
NCERT (Pre-rationalised edition, 2022-23):
Interhalogen Compounds – “… These are all covalent molecules and are diamagnetic in nature. They are volatile solids or liquids except ClF which is a gas at 298 K. Their physical properties are intermediate between those of constituent halogens except that their m.p. and b.p. are a little higher than expected.”