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Q.
The compound that cannot act both as oxidising and reducing agent is
NTA AbhyasNTA Abhyas 2022
Solution:
$H_{2}O_{2}^{- 1}$ $H_{2}SO_{3}^{+ 4}$ $\overset{+ 3}{H N O_{2}}$
As in $H_{3}PO_{4}$ phosphorous is in maximum oxidation state +5 so it can not undergo oxidation or can be reduced only so it is an oxidant only.