Question

Suppose you wish to extract 10 g of benzoic acid from an ether solution with aqueous NaHCO3. What is the minimum amount of NaHCO3 that must be added to 50 mL of water to carry out the extraction?

Answer 1

Answer:

Minimum amount of $NaHCO_3$ = 6.88 g

Explanation:

Benzoic acid reacts with $NaHCO_3$ as:

$C_6H_5COOH + NaHCO_3 \rightarrow C_6H_5COONa + CO_2 + H_2O$

Molar mass of $C_6H_5COOH$ = 122 g/mol

Molar mass of $NaHCO_3$=84 g/mol

No. of moles of $C_6H_5COOH$ = $\frac{10}{122} mol$

From reaction,

1 mol of $C_6H_5COOH$ reacts with 1 mol of $NaHCO_3$

$\frac{10}{122} mol$ mol of $C_6H_5COOH$ will react with

                             = $\frac{10}{122} mol$ of $NaHCO_3$

Mass of $NaHCO_3$ in g = No. of mol × Molar mass

                                                     = $=\frac{10}{122} \times 84 = 6.88\ g$