Question

The compound that cannot act both as oxidising and reducing agent is :

(1) H₂O₂ 

(2) H₂SO₃

(3) HNO₂ 

(4) H₃PO₄

Answer 1

Answer is (4)

(i) H₂O₂ act as oxidising agent as well as reducing agent depending on condition. 

(ii) H₂SO₃ act as oxidising agent as well as reducing agent depending on condition. 

(iii) HNO₂ act as oxidising agent as well as reducing agent depending on condition. 

(iv) H₃PO₄ can not act both as oxidising and reducing agent. 

H₃PO₄ can act as only oxidising agent.

Answer 2

Answer is (4)

H₃ PO₄ , oxidation no. of 'P' is +5 which is maximum.

Hence it can act as oxidising agent.