Chapter U5.116, Problem 3E

Interpretation Introduction

Interpretation:

The effect of the sunlight on a UV-sensitive paper needs to be explained.

Concept introduction:

The sun sensitive paper is coated with chemicals which sensitive to light. They react with light falling on them from sun.

UV sensitive paper is also known as light sensitive or photo sensitive paper. It is made by coating with water soluble bluish-green compound which is commonly known as Berlin-Green.

Answer to Problem 3E

It changes the color of the UV sensitive paper from green to Prussian blue by a chemical reaction.

Explanation of Solution

UV sensitive paper is also known as light sensitive or photo sensitive paper because it respond to light which comes from sun.

This paper is coating with a bluish-green compound which is water soluble and commonly known as Berlin-Green. Its chemical name is iron(III) hexacyanferrate (III) and chemical formula is Fe[Fe(CN)₆]. When this UV sensitive paper is exposed to sun, Berlin-Green transform into a chemical complex which is water insoluble that is Prussian blue compound. Its chemical name is iron(III) hexacyanferrate (II),Fe[Fe₄(CN)₆]₃.

This reaction is mainly in present of UV rays that comes from sun light and allow them to react to form this new insoluble compound.

Conclusion

When UV sensitive paper exposed to sun light its color changes from green to Prussian blue by chemical reaction.