Statement 1: Non-metallic oxides are usually basic anhydrides.
Statement 2: Non-metallic oxides form acid when placed in water.
(A) Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1.
(B) Both Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation of Statement 1.
(C) Statement 1 is correct but Statement 2 is not correct.
(D) Statement 1 is not correct but Statement 2 is correct.

Hint: To answer this question, we should know that non-metals react with oxygen to form non-metal oxides. The reactions of carbon and sulphur with oxygen are examples of non-metals reacting with oxygen. And they are called non-metallic oxides.

Complete step by step answer:
> To prove the statement, we should know that non-metals gain or share electrons when they react with other elements and chemical compounds. From the periodic table, we can tell seventeen elements are generally classified as non-metals: most are gases (hydrogen, helium, nitrogen, oxygen, fluorine, neon, chlorine, argon, krypton, xenon and radon); one is a liquid (bromine); and a few are solids (carbon, phosphorus, sulphur, selenium, and iodine).
> When the above present non-metals react with oxygen, they form non-metal oxides. They are acid anhydride. We can say that acid anhydride is those in which if we add water it will form acid. Acid anhydrides are non-metal oxides.
> So, from the above discussion we can say that non-metallic oxides are acidic anhydrides. So, from this statement 1 is incorrect. And in the second statement it says that non-metal oxides form acid when placed in water. So, this statement is correct. So, from this we can say that option D is correct.

Note: We know about acid anhydrides, now we will know about basic anhydrides. We should know that oxides of metallic oxides are called basic anhydrides. And when we add water in basic anhydrides they may form bases.