Question

Which of the following statements is not correct?
A. All halogens except fluorine from OXO-acids
B. Hypohalous acids HOCL, HOBr and HOI are all strong acids
C. Hypochlorous acids is the most stable among hypohalous acids
D. Chlorous acid is the only halous acid known

Answer 1

Hint: There are other halous acids too and also all the halogens form oxo-acids except one of them. perchloric acid is the strongest of all known simple acids. chlorous acid , bromous acid and iodous acid all are unstable

Complete step by step answer:
There are also other halous acids present like:
$HOBr_2$​ which is Hydrobromic acid.
Therefore Chlorous acid is not the only one halous acid present.
Hence, Option D is not correct.
A halous acid, is also termed as a halogenous acid, which is an oxyacid consisting of a halogen atom in the oxidation state plus three which is single-bonded to a hydroxyl group and also double-bonded to an oxygen atom. Examples involve chlorous acid, bromous acid, and iodous acid and the conjugate base is a halite.

So, the correct answer is Option D.

Additional Information:
Halogens are highly reactive in nature, and they can be very harmful or lethal to biological organisms in enough quantities. This known reactivity is because of high electronegativity along with high effective nuclear charge. Halogens can add an electron by treating it with atoms of other elements. Fluorine is one of the most reactive nature elements.
Fluorine gas is pale yellow in colour, and chlorine gas is generally yellowish green. Liquid bromine along with its vapours are brownish red. Solid iodine looks like shiny, dark grey crystals, and its vapours are deep purple. The halogens are usually poor thermal and electrical conductors in all the phases, and as for solids, they are brittle and crumbly.

Note: Halogens are non-metals. At room temperature, fluorine and chlorine acts as gases and bromine is a liquid. Iodine and astatine are solids. Halogens are very reactive gases, the reactivity decreases from fluorine to astatine.