Q78E - Chemistry (OpenStax)

Question

What volume of 0.0105-M HBr solution is required to titrate 125 mL of a 0.0100-M Ca(OH)₂ solution?

 

Ca(OH)₂(aq) + 2HBr(aq) ⟶ CaBr₂(aq) + 2H₂ O(l)

Step-by-Step Solution

Answer

238 mL of 0.0105-M HBr solution is required to titrate 125 mL of a 0.0100-M Ca(OH)₂ solution

Given data

This titration is between acid and base. For this formula we use 

\({M_a}{V_a} = {M_b}{V_b}\)

where a = acid (HBr) and     b = base (Ca(OH)2)

 

Molarity of HBr =   0.0105 M       and     Volume of HBr =??

 

Molarity of Ca(OH)₂  = 0.0100 M       Volume of Ca(OH)₂ = 125 mL

Determine volume of HBr

Ca(OH)₂(aq) + 2HBr(aq) ⟶ CaBr₂(aq) + 2H₂ O(l)

\({M_a}{V_a} = {M_b}{V_b}\)       

By putting the values in the above equation,

\(\begin{aligned}{\underline{\phantom{xx}}}1 \times 0.0105M \times X = 0.0100\,M \times 2 \times 125\,mL\\X = \frac{{0.0100\,M \times 2 \times 125\,mL}}{{0.0105M}}\\X = 238.09\,mL\end{aligned}\)

        238 mL  of HBr