4.5 g of compound.A (MW=90) was used to make 250 mL of its aqueous solution. The molarity of the solution in Mis `"x"xx10^(-1)`. The value of x is
(Rounded off to the nearest integer)

Answer

To find the molarity of the solution, we can follow these steps:

### Step 1: Calculate the number of moles of the compound
The number of moles (n) can be calculated using the formula:
\[ n = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}} \]
Given:
- Mass of compound A = 4.5 g
- Molar mass of compound A = 90 g/mol

Substituting the values:
\[ n = \frac{4.5 \, \text{g}}{90 \, \text{g/mol}} = 0.05 \, \text{mol} \]

### Step 2: Convert the volume from mL to L
The volume of the solution is given in mL, and we need to convert it to liters:
\[ \text{Volume (L)} = \frac{\text{Volume (mL)}}{1000} \]
Given:
- Volume = 250 mL

Calculating the volume in liters:
\[ \text{Volume (L)} = \frac{250 \, \text{mL}}{1000} = 0.25 \, \text{L} \]

### Step 3: Calculate the molarity of the solution
Molarity (M) is defined as the number of moles of solute per liter of solution:
\[ M = \frac{n}{\text{Volume (L)}} \]
Substituting the values:
\[ M = \frac{0.05 \, \text{mol}}{0.25 \, \text{L}} = 0.2 \, \text{M} \]

### Step 4: Express the molarity in the required format
The problem states that the molarity is in the form of \( x \times 10^{-1} \). Here, we have:
\[ 0.2 \, \text{M} = 2 \times 10^{-1} \, \text{M} \]
Thus, the value of \( x \) is 2.

### Final Answer
The value of \( x \) is **2**.

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