The equivalent mass of calcium phosphate `Ca_(3) ( PO_(4))_(2)` ( Mol. wt. = 310 ) is -

Options

A. `310 //2`
B. `310 //6`
C. `310 //3`
D. 310

Answer

To find the equivalent mass of calcium phosphate \( Ca_3(PO_4)_2 \), we can follow these steps:

### Step 1: Identify the Molecular Weight
The molecular weight of calcium phosphate \( Ca_3(PO_4)_2 \) is given as 310 g/mol.

### Step 2: Determine the Ionization of Calcium Phosphate
When calcium phosphate dissociates in solution, it produces calcium ions and phosphate ions:
\[ Ca_3(PO_4)_2 \rightarrow 3Ca^{2+} + 2PO_4^{3-} \]
From this dissociation, we can see that there are 3 calcium ions (each with a charge of +2) and 2 phosphate ions (each with a charge of -3).

### Step 3: Calculate the Total Charge
Next, we need to calculate the total charge contributed by the ions:
- The total positive charge from calcium ions:
\[ 3 \times (+2) = +6 \]
- The total negative charge from phosphate ions:
\[ 2 \times (-3) = -6 \]
The total charge (considering both cations and anions) is therefore 6.

### Step 4: Use the Formula for Equivalent Mass
The equivalent mass of a compound can be calculated using the formula:
\[ \text{Equivalent Mass} = \frac{\text{Molecular Weight}}{\text{Total Charge}} \]
Substituting the values we have:
\[ \text{Equivalent Mass} = \frac{310 \, \text{g/mol}}{6} \]

### Step 5: Perform the Calculation
Now, we perform the calculation:
\[ \text{Equivalent Mass} = \frac{310}{6} \approx 51.67 \, \text{g/equiv} \]

### Conclusion
The equivalent mass of calcium phosphate \( Ca_3(PO_4)_2 \) is approximately **51.67 g/equiv**.

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