Question

a chemistry student weighs out 0.0849 g of formic acid (hcho₂) into a 250. ml volumetric flask and dilutes to the mark with distilled water. he plans to titrate the acid with 0.0700m naoh solution. calculate the volume of naoh solution the student will need to add to reach the equivalence point. round your answer to 3 significant digits

Explanation:

Step1: Calculate the moles of formic acid

The molar mass of \(HCHO_2\) is \(M=(1\times2 + 12+16\times2)\space g/mol=46\space g/mol\).
The moles of \(HCHO_2\), \(n=\frac{m}{M}\), where \(m = 0.0849\space g\) and \(M = 46\space g/mol\). So \(n=\frac{0.0849\space g}{46\space g/mol}=0.00184565\space mol\)

Step2: Use the stoichiometry of the reaction

The reaction between \(HCHO_2\) and \(NaOH\) is \(HCHO_2+NaOH
ightarrow NaCHO_2 + H_2O\). The mole ratio of \(HCHO_2:NaOH = 1:1\). So the moles of \(NaOH\) required for equivalence point is \(n_{NaOH}=n_{HCHO_2}=0.00184565\space mol\)

Step3: Calculate the volume of \(NaOH\) solution

We know that \(M=\frac{n}{V}\) (where \(M = 0.0700\space M\) is the molarity of \(NaOH\) solution). Rearranging for \(V\), we get \(V=\frac{n}{M}\)
Substitute \(n = 0.00184565\space mol\) and \(M=0.0700\space mol/L\)
\(V=\frac{0.00184565\space mol}{0.0700\space mol/L}=0.0263664\space L\)

Convert liters to milliliters: \(V = 0.0263664\space L\times1000\space mL/L = 26.4\space mL\) (rounded to 3 significant digits)

Answer:

\(26.4\space mL\)