The exact volumes of 1 M NaOH solution required to neutralise 50 mL of 1 M H₃PO₃ solution and 100 mL of 2 M H₃PO₂ solution, respectively, are :

The characteristics of elements X, Y and Z with atomic numbers, respectively, 33, 53 and 83 are :

Which of the following is least basic?

The correct statements about H₂O₂ are :

(A) used in the treatment of effluents.

(B) used as both oxidising and reducing agents.

(C) the two hydroxyl groups lie in the same plane.

(D) miscible with water.

Choose the correct answer from the options given below :