Question

Which of the following is not correct?

• A. $H_{2}O_{2}$ oxidizes Fe (II) to Fe (III)
• B. $H_{2}O_{2}$ is a weak base
• C. $H_{2}O_{2}$ can be obtained by the electrolysis of dil. $H_{2}SO_{4}$
• D. $H_{2}O_{2}$ reduces Mn (VII) to Mn (II)

Answer 1

Answer: (B)

$H_{2}O_{2}$ is weakly acidic, but more acidic than water.
$H_{2}O_{2}+H_{2}O \rightarrow H_{3}O^{+}+HO_{2}^{-}$
A. $2Fe^{2 +}+H_{2}O_{2}+2H^{+} \rightarrow 2Fe^{3 +}+2H_{2}O$
C. $H_{2}SO_{4}\rightleftharpoonsH^{+}+HSO_{4}^{-}$
Anode $2HSO_{4}^{-} \rightarrow H_{2}S_{2}O_{8}+2e^{-}$
Cathode $2H^{+}+2e^{-} \rightarrow H_{2}$
The peroxy disulphuric acid is hydrolysed separately to get $H_{2}O_{2}$ .
$H_{2}S_{2}O_{8}+H_{2}O \rightarrow H_{2}SO_{5}+H_{2}SO_{4}$
$H_{2}SO_{5}+H_{2}O \rightarrow H_{2}SO_{4}+H_{2}O_{2}$
D. $2MnO_{4}^{-}+5H_{2}O_{2}+6H^{+} \rightarrow 2Mn^{2 +}+8H_{2}O+5O_{2}$