Calculation of Equivalent Weight of an Acid

To calculate the equivalent weight of an acid, we need to consider the following information:

- The amount of acid used in the neutralization reaction
- The volume of the base solution
- The normality (N) of the base solution

Given:

- Amount of acid used: 0.126 g
- Volume of base solution: 20 mL
- Normality of NaOH: 0.1 N

Step 1: Convert Volume to Liters

Since the normality of the base solution is given in liters, we need to convert the volume of the base solution from milliliters to liters.

1 mL = 0.001 L

Therefore, the volume of the base solution in liters is:
20 mL × 0.001 L/mL = 0.02 L

Step 2: Calculate the Number of Moles of NaOH

To calculate the number of moles of NaOH used in the neutralization reaction, we can use the formula:

Number of moles = Normality × Volume (in liters)

Number of moles of NaOH = 0.1 N × 0.02 L = 0.002 moles

Step 3: Determine the Molecular Weight of NaOH

The molecular weight of NaOH is calculated by adding the atomic masses of sodium (Na), oxygen (O), and hydrogen (H).

Na: 22.99 g/mol
O: 16.00 g/mol
H: 1.01 g/mol

Molecular weight of NaOH = 22.99 g/mol + 16.00 g/mol + 1.01 g/mol = 40.00 g/mol

Step 4: Calculate the Number of Moles of Acid

To calculate the number of moles of acid, we can use the formula:

Number of moles = Mass / Molecular weight

Number of moles of acid = 0.126 g / Molecular weight

Step 5: Calculate the Equivalent Weight of the Acid

The equivalent weight of an acid is the mass of the acid that reacts with one equivalent of a base. It is calculated by dividing the mass of the acid by the number of moles of acid.

Equivalent weight = Mass / Number of moles

Equivalent weight = 0.126 g / (0.126 g / Molecular weight) = Molecular weight

Therefore, the equivalent weight of the acid is equal to its molecular weight.

Conclusion:

In this case, the equivalent weight of the acid is equal to its molecular weight, which needs to be determined using the given information.