Step-by-step explanation:
butanoic acid has four carbon atoms, with last carbon being the carbonyl carbon
![{ \tt{CH _(3)CH _(2)CH _(2) C OOH}}](https://img.qammunity.org/2022/formulas/chemistry/college/pt3t7bq41thjjq54np8v77fzm8sfv3dh10.png)
• chlorine molecule is on the third carbon from the right hand side [ carboxylic group side ]
![{ \tt{CH _(3)CH(Cl) _{}CH _(2) C OOH}}](https://img.qammunity.org/2022/formulas/chemistry/college/5rbcejc1wgmsya3ebgddryaea6rqv12ous.png)
• hydroxyl molecule is on the fourth carbon fromright hand side.
![{ \tt{(OH)CH _(2)CH(Cl) _{}CH _(2) C OOH}}](https://img.qammunity.org/2022/formulas/chemistry/college/5qc4qznt2x1cuuga3bug29ygpy02m9x8xt.png)