It can be separated by physical means and is not uniform in composition.
The oxidation number of S in H2SO is +0.
The oxidation number of O in H2SO is -2.
The oxidation number of H in H2SO is +1
Answer: 0.52 L of 15 M 
will be used to prepare this amount of 0.52 M base.
Explanation:
But on diluting the number of moles remain same and thus we can use molarity equation.
(to be prepared)
where,
=concentration of stock solution = 15 M
= volume of stock solution = ?
= concentration of solution to be prepared = 0.52 M
= volume of solution to be prepared = 15 L
Thus 0.52 L of 15 M will be used to prepare this amount of 0.52 M base
Condensation.
If you think about the condensation you may find on your windows on a frosty morning, this may help you to remember :]
