A 5.0 cm³ solution of H₂O₂ liberates 0.508 g of iodine from an acidified KI solution. Calculate the strength of H₂O₂ solution in terms of volume strength at STP.

Complete and balance the following reactions:
Ca₅(PO₄)₃F + H₂SO₄ + H₂O $$\buildrel {Heat} \over \longrightarrow $$ ........ + 5CaSO₄.2H₂O + ........

Give briefly the isolation of magnesium from sea water by the Dow process. Give equations for the steps involved.

Give reasons of the following:
Hydrogen peroxide acts as an oxidising as well as a reducing agent.