The equivalent weight of oxalic acid in `C_(2)H_(2)O_(4). 2H_(2)O` is

Options

A. 45
B. 63
C. 90
D. 126

Answer

To find the equivalent weight of oxalic acid in `C2H2O4.2H2O`, we will follow these steps:

### Step 1: Calculate the Molecular Weight of `C2H2O4.2H2O`
The molecular formula of oxalic acid dihydrate is `C2H2O4.2H2O`. We will calculate the molecular weight by adding the atomic weights of all the atoms in the formula.

- Carbon (C): 12 g/mol × 2 = 24 g/mol
- Hydrogen (H): 1 g/mol × 2 = 2 g/mol
- Oxygen (O): 16 g/mol × 4 = 64 g/mol
- Water (H2O): 18 g/mol × 2 = 36 g/mol

Now, add these values together:
\[ \text{Molecular weight} = 24 + 2 + 64 + 36 = 126 \text{ g/mol} \]

### Step 2: Determine the n-factor
The n-factor for an acid is determined by the number of replaceable hydrogen ions (H⁺) it can donate. For oxalic acid (`C2H2O4`), it can donate 2 hydrogen ions.

Thus, the n-factor (number of replaceable H⁺ ions) = 2.

### Step 3: Calculate the Equivalent Weight
The formula for equivalent weight is given by:
\[ \text{Equivalent weight} = \frac{\text{Molecular weight}}{\text{n-factor}} \]

Substituting the values we have:
\[ \text{Equivalent weight} = \frac{126 \text{ g/mol}}{2} = 63 \text{ g/equiv} \]

### Conclusion
The equivalent weight of oxalic acid in `C2H2O4.2H2O` is **63 g/equiv**.

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