`20 g` of an acid furnishes `0.5 "mole of" H_(3)O^(+)` ions in its aqueous solution. The value of `1` equivalent of the acid will be:

Options

A. `40 g`
B. `20 g`
C. `10 g`
D. `100 g`

Explanation

To find the value of 1 equivalent of the acid, we can follow these steps:

### Step 1: Understand the relationship between moles and equivalents
1 equivalent of an acid is defined as the amount of acid that can furnish 1 mole of H⁺ ions (or H₃O⁺ ions in aqueous solution).

### Step 2: Calculate the number of equivalents in the given mass of acid
Given that 20 g of the acid furnishes 0.5 moles of H₃O⁺ ions, we can determine the number of equivalents of the acid.

- Since 0.5 moles of H₃O⁺ corresponds to 0.5 equivalents of the acid, we can say:
\[ \text{Number of equivalents} = 0.5 \]

### Step 3: Calculate the equivalent weight of the acid
To find the equivalent weight of the acid, we use the formula:
\[ \text{Equivalent weight} = \frac{\text{Weight of acid}}{\text{Number of equivalents}} \]

Substituting the known values:
\[ \text{Equivalent weight} = \frac{20 \, \text{g}}{0.5} = 40 \, \text{g/equiv} \]

### Conclusion
Thus, the value of 1 equivalent of the acid is **40 g**.

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