Pblock Elementsii Result Question 29
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.
(2012)
29. Bleaching powder contains a salt of an oxoacid as one of its components. The anhydride of that oxoacid is
(a) $\mathrm{Cl} _2 \mathrm{O}$
(b) $\mathrm{Cl} _2 \mathrm{O} _7$
(c) $\mathrm{ClO} _2$
(d) $\mathrm{Cl} _2 \mathrm{O} _6$
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Answer:
Correct Answer: 29. ( a )
Solution:
Bleaching powder is $\mathrm{Ca}(\mathrm{OCl}) \mathrm{Cl}$. Therefore, the oxoacid whose salt is present in bleaching powder is $\mathrm{HOCl}$. Anhydride of $\mathrm{HOCl}$ is $\mathrm{Cl} _2 \mathrm{O}$ as
$2 \mathrm{HOCl} \longrightarrow \mathrm{Cl} _2 \mathrm{O}+\mathrm{H} _2 \mathrm{O}$
NOTE The oxidation number of element in anhydride and oxoacid** remains the same
BETA
