A total of 31.3 ml of 0.15 N NaOH was required to reach a phenolphthalein endpoint in titrating 6.00 g of vinegar. Calculate the number of equivalents of acetic acid in vinegar.
To calculate the number of equivalents of acetic acid in vinegar, we need to use the equation:
equivalents = (volume of NaOH (in liters) x normality of NaOH) / equivalent weight of acetic acid
First, let's convert the volume of NaOH from milliliters to liters:
31.3 ml = 0.0313 L
Next, let's calculate the number of equivalents of acetic acid using the information given:
equivalents = (0.0313 L x 0.15 N) / equivalent weight of acetic acid
The equivalent weight of acetic acid is the molar mass of acetic acid divided by the number of acidic hydrogens. Acetic acid has only one acidic hydrogen.
The molar mass of acetic acid is 60.052 g/mol.
So, the equivalent weight of acetic acid = 60.052 g/mol / 1 = 60.052 g/equivalent
Now, let's substitute the values into the equation:
equivalents = (0.0313 L x 0.15 N) / 60.052 g/equivalent
Calculating the equation gives us:
equivalents = 0.004695 equivalents
Therefore, there are approximately 0.004695 equivalents of acetic acid in 6.00 g of vinegar.