Question

0.2 g sample of benzoic acid, $C_{6}H_{5}COOH$ is titrated with 0.12 M Ba $\left(O H\right)_{2}$ solution. What volume of $Ba ( OH )_{2}$ solution is required to reach the equivalence point?

Molar mass of benzoic acid is 122 g $mol^{- 1}$ .

• A. 6.83 mL
• B. 13.6 mL
• C. 17.6 mL
• D. 35.2 mL

Answer 1

Answer: (A)

Number of moles of benzoic acid $=\frac{0.2}{122}=1.64 \times 10^{-3}$

Neutralization takes place as $2 C _{6} H _{5} COOH + Ba ( OH )_{2} \rightarrow\left( C _{6} H _{5} COO \right)_{2} Ba +2 H _{2} O$

Number of moles of $Ba ( OH )_{2}$ required $=\frac{1}{2} \times 1.64 \times 10^{-3}$

$\frac{ MV }{ l 000}=\frac{1}{2} \times 1.64 \times 10^{-3}$

$\frac{0.12 \times V }{1000}=\frac{1}{2} \times 1.64 \times 10^{-3}$

$V=6.83 mL$