Mohr's salt, also known as ammonium iron(II) sulfate, is a double salt with the formula FeSO4(NH4)2SO4·xH2O. The value of x represents the number of water molecules associated with each formula unit of the salt. In the case of Mohr's salt, x is equal to 6.

- Definition of Mohr's Salt
Mohr's salt is a coordination compound that consists of two different cations, ammonium (NH4+) and iron(II) (Fe2+), and two different anions, sulfate (SO42-) and sulfate (SO42-). It is classified as a double salt because it contains two different metal ions.

- Formula of Mohr's Salt
The formula of Mohr's salt is FeSO4(NH4)2SO4·xH2O. This formula indicates that there are two ammonium ions (NH4+) and one iron(II) ion (Fe2+) in the salt. The iron(II) ion is coordinated to four sulfate ions (SO42-), while each ammonium ion is coordinated to one sulfate ion. The value of x represents the number of water molecules associated with each formula unit of the salt.

- Significance of Water Molecules
In the case of Mohr's salt, the water molecules are known as water of crystallization or water of hydration. These water molecules are incorporated into the crystal lattice of the salt during its formation, and they play a significant role in the physical and chemical properties of the compound.

- Explanation of Value of x
The value of x in the formula FeSO4(NH4)2SO4·xH2O represents the number of water molecules associated with each formula unit of the salt. In the case of Mohr's salt, x is equal to 6. This means that for every formula unit of Mohr's salt, there are six water molecules associated with it.

- Importance of Water of Crystallization
The water molecules in Mohr's salt are held in the crystal lattice through hydrogen bonding with the ions of the salt. These water molecules can be easily removed by heating the salt, resulting in the formation of an anhydrous compound. The loss of water of crystallization can lead to changes in the physical properties of the salt, such as color and solubility.

In conclusion, the value of x in the formula FeSO4(NH4)2SO4·xH2O represents the number of water molecules associated with each formula unit of Mohr's salt. In the case of Mohr's salt, x is equal to 6, indicating that there are six water molecules associated with each formula unit of the salt.