Problem 52 - Chemistry: The Central Science

Question

Write a balanced chemical equation using condensed structural formulas for (a) the formation of butyl propionate from the appropriate acid and alcohol, (b) the saponification (base hydrolysis) of methyl benzoate.

Step-by-Step Solution

Answer

a) Formation of butyl propionate: \(\text{CH3CH2COOH + CH3(CH2)3OH} \rightarrow \text{CH3CH2COO(CH2)3CH3 + H2O}\) b) Saponification of methyl benzoate: \(\text{C6H5COOCH3 + NaOH} \rightarrow \text{C6H5COONa + CH3OH}\)

Step 1: a) Identify acid and alcohol precursors for butyl propionate formation

To form butyl propionate, we need a propionic acid and a butyl alcohol precursor. Propionic acid has the condensed structural formula CH3CH2COOH, and butyl alcohol (also called butanol) has the condensed structural formula CH3(CH2)3OH. These two compounds will react in an esterification reaction to form butyl propionate and water.

Step 2: a) Write the balanced equation for the formation of butyl propionate

The esterification reaction between propionic acid and butanol can be written as follows: $$\text{CH3CH2COOH + CH3(CH2)3OH} \rightarrow \text{CH3CH2COO(CH2)3CH3 + H2O}$$ This represents the formation of butyl propionate (CH3CH2COO(CH2)3CH3) and water.

Step 3: b) Write the balanced equation for saponification of methyl benzoate

For saponification, we need a base, typically sodium hydroxide (NaOH), to hydrolyze the ester linkage in methyl benzoate. Methyl benzoate has the condensed structural formula C6H5COOCH3. When it undergoes saponification, it forms sodium benzoate (the carboxylate salt, C6H5COONa) and methanol (CH3OH). The balanced equation can be written as follows: $$\text{C6H5COOCH3 + NaOH} \rightarrow \text{C6H5COONa + CH3OH}$$ This represents the saponification (base hydrolysis) of methyl benzoate into sodium benzoate and methanol.