Question

Given :
$O_2\left(g\right)+4H^{\oplus }\left(aq\right)+4e^{-}\to 2H_{2}O\left(l\right)$
$E^{\oplus }=1.23V$
$S_2{O}_8^{2-}\left(aq\right)+2e^{-}\to 2S{O}_2^{4-}\left(aq\right)$
$E^{\ominus }=2.01V$

Assertion: Peroxodisulphate salts $(e.g.,N{a}_2{S}_2{O}_8)$ are strong oxidizing agents used as bleaching agents for fats, oils, and fabrics.

Reason: Oxygen gas can oxidize sulphate ion to peroxodisulphate ion $\left(S_2{O}_8^{2-}\right)$ in acidic solution, with the $O_2\left(g\right)$ being reduced to water.

• A. Both Assertion and Reason are true and Reason is the correct explanation of Assertion
• B. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
• C. Assertion is true but Reason is false
• D. Assertion is false but Reason is true
• E. Both Assertion and Reason are false

Answer 1

The correct option is B Both Assertion and Reason are true but Reason is not the correct explanation of Assertion

Anode : $2S{O}_4^{2-}\to S_2{O}_8^{2-}+2e^{-}$
$E^{\ominus }=2.01V$
Cathode : $O_2+4H^{\oplus }+4e^{-}\to 2H_{2}O$
$E^{\ominus }=1.23V$
$E_{cell}^{\ominus }=1.23-2.01=-0.78V<0$
$\Rightarrow O_2$ can oxidize $S{O}_4^{2-}$ to $S_2{O}_8^{2-}$.