Calculate the volume of 0.1 M NaOH solution required to neutralise the products formed by dissolving 1.1 g of P₄O₆ in H₂O.

Reaction of P₄O₆ in H₂O is:

The reaction of Phosphorous acid with water is:

The above two reactions can be written in combined form:

1 mole of is neutralized by 8 moles of NaOH

of P₄O₆ will be neutralized by moles of NaOH

Molarity of NaOH solution is 0.1 M i.e. 0.1 mole is present in 1 L of water

So, moles of NaOH will be present in =

The volume of 0.1 M NaOH required is 0.4 L or 400 mL.