Why cannot we concentrate hydrogen preoxide solution on direct heating?

Why can dilute solutions of hydrogen peroxide not be concentrated by heating? How can a conentrated solution of hydrogen peroxide be obtanied ?

Why cannot we hear an echo in a small room ?

Why cannot the dilute solution of hydrogen peroxide be concentrated by strong heating?

Hydrogen peroxide (H_2 O_2) was first prepared by Thenard by acidifying barium peroxide and removal of excess water by evaporation under reduced pressure. Its strength can be expressed as weigth percentage or as volume percentage . 25% solution by weight means 25 g of hydrogen peroxide are present in 100 g of solution and 25 volume of hydrogen peroxide means that 1 litre of this solution will give 25 L of oxygen at NTP. Why can dilute solution of hydrogen peroxide not be concentrated by heating ?

The pH of solution is 4.0 what should be the change in the hydrogen ion concentration of the solution if its pH is to be increased to 5.0

Why cannot we obtain interference using two independent source of light ?