Question

X is a pink solid. Y is a blue solid. When X is heated, water is produced and the solid turns blue. When water is added to Y, the solid turns pink. What are X and Y?

A) anhydrous cobalt (II) chloride, hydrated cobalt(II)chloride


B) hydrated cobalt (II) chloride, anhydrous cobalt (II) chloride


C) anhydrous copper(II) sulfate, hydrated copper (II) sulfate


D) hydrated copper (II) sulfate, anhydrous copper (II) sulfate

Answer 1

The answer is D: hydrated copper (II) sulfate, anhydrous copper (II) sulfate.

The key pieces of information are:

• X is a pink solid. When X is heated, water is produced and the solid turns blue.

This describes the property of hydrated copper (II) sulfate. When hydrated copper (II) sulfate is heated, it loses water molecules and turns from pink to blue.

• When water is added to Y, the solid turns pink.

This describes the property of anhydrous copper (II) sulfate. When water is added, it absorbs water molecules and turns from blue to pink.

Cobalt (II) chloride mentioned in the other answers does not exhibit these color changes based on hydration/dehydration. Only copper (II) sulfate turns pink when hydrated and blue when anhydrous.

So the full answers are:

X = hydrated copper (II) sulfate

Y = anhydrous copper (II) sulfate

Hope this explanation helps! Let me know if you have any other questions.