Dow's process of extraction of Mg involves extraction of Mg from sea water. Sea water is concentrated in sun-light and is then treated with slaked lime. Magnesium hydroxide is heated in a stream of HCl to give `MgCl_(2)` which is electrolysed to discharge Mg. The mixture is in the ratio 35% `MgCl_(2)+50% NaCl+15% CaCl_(2)`. NaCl and `CaCl_(2)` are added to lower the fusion temperature and to increases the conductance.
`Mg^(2+) +Ca(OH)_(2) to Mg(OH)_(2)+Ca^(2+)`
`Mg(OH)_(2)+2HCl to MgCl_(2)+2H_(2)O(l)`
Electrolysis of fused `MgCl_(2) hArr Mg^(2+)+2Cl`
`Mg^(2+)+2e^(-) to Mg`( At Cathode)
`2Cl^(-) to Cl_(2)+2e^(-)` (At Anode)
Mg electrolysed is protected from atmospheric oxidation by a blanket of inert gases.
In the hydrated chloride of Mg the value of x is :

Options

A. 6
B. 4
C. 8
D. 10

Answer

To determine the value of \( x \) in the hydrated chloride of magnesium, we need to analyze the process of obtaining magnesium chloride from seawater and its subsequent hydration. Here’s a step-by-step breakdown of the solution:

### Step 1: Understanding the Dow's Process
- The Dow's process involves the extraction of magnesium from seawater, where magnesium ions are concentrated and treated with slaked lime (calcium hydroxide).
- The reaction is:
\[ \text{Mg}^{2+} + \text{Ca(OH)}_2 \rightarrow \text{Mg(OH)}_2 + \text{Ca}^{2+} \]
- This results in the formation of magnesium hydroxide, which is a white precipitate.

### Step 2: Converting Magnesium Hydroxide to Magnesium Chloride
- The magnesium hydroxide is then treated with hydrochloric acid (HCl) to produce magnesium chloride:
\[ \text{Mg(OH)}_2 + 2\text{HCl} \rightarrow \text{MgCl}_2 + 2\text{H}_2\text{O} \]
- This reaction yields magnesium chloride in an aqueous form.

### Step 3: Hydration of Magnesium Chloride
- The aqueous magnesium chloride can crystallize to form hydrated magnesium chloride, which is typically represented as:
\[ \text{MgCl}_2 \cdot x\text{H}_2\text{O} \]
- The common hydrated form of magnesium chloride is hexahydrate, represented as:
\[ \text{MgCl}_2 \cdot 6\text{H}_2\text{O} \]

### Step 4: Identifying the Value of \( x \)
- From the crystallization process, we know that magnesium chloride commonly forms a hexahydrate.
- Therefore, in the hydrated chloride of magnesium, the value of \( x \) is 6.

### Final Answer
- The value of \( x \) in the hydrated chloride of magnesium is:
\[ x = 6 \]