JEE Challenger
More from p-Block Elements (Group 15-18)
ChemEasyAdv 2012 • Paper 2

Anhydride of Oxoacid Component in Bleaching Powder

Comprehension Passage

Bleaching powder and bleach solution are produced on a large scale and used in several household products. The effectiveness of bleach solution is often measured by iodometry.

Bleaching powder contains a salt of an oxoacid as one of its components. The anhydride of that oxoacid is

Options

A

Cl2O\text{Cl}_2\text{O}

Correct
B

Cl2O7\text{Cl}_2\text{O}_7

C

ClO2\text{ClO}_2

D

Cl2O6\text{Cl}_2\text{O}_6

Topics & Concepts

p-Block Elements (Group 15-18)p-Block Elements

Step-by-Step Solution

Bleaching powder is chemically represented as CaOCl2\text{CaOCl}_2 or Ca(OCl)Cl⋅H2O\text{Ca(OCl)Cl}\cdot\text{H}_2\text{O}. It contains the hypochlorite anion (OCl−\text{OCl}^-), which is the conjugate base of hypochlorous acid (HOCl\text{HOCl}).

To determine the acid anhydride of an oxoacid, we remove a molecule of water (H2O\text{H}_2\text{O}) from two molecules of the acid:

2HOCl→−H2OCl2O2\text{HOCl} \xrightarrow{-\text{H}_2\text{O}} \text{Cl}_2\text{O}

Thus, dichlorine monoxide (Cl2O\text{Cl}_2\text{O}) is the anhydride of hypochlorous acid (HOCl\text{HOCl}).

Therefore, the correct option is (A).

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