To convert a primary alcohol to a carboxylic acid, a strong oxidizing agent is required. The given conversion is from cyclohexylmethanol (a primary alcohol) to cyclohexanecarboxylic acid (a carboxylic acid). The reaction is: $$ \text{Cyclohexylmethanol} \xrightarrow{\text{Reagent}} \text{Cyclohexanecarboxylic acid} $$ A common strong oxidizing agent used for this transformation is potassium permanganate ($\text{KMnO}_4$) under acidic or basic conditions, followed by acidification. Another strong oxidizing agent is the Jones reagent ($\text{CrO}_3$ in $\text{H}_2\text{SO}_4$ and acetone). Step 1: Identify the functional groups. The reactant is a primary alcohol: $-\text{CH}_2\text{OH}$. The product is a carboxylic acid: $-\text{COOH}$. Step 2: Determine the type of reaction. The conversion of a primary alcohol to a carboxylic acid involves oxidation. Step 3: Select an appropriate strong oxidizing agent. For the complete oxidation of a primary alcohol to a carboxylic acid, a strong oxidizing agent is necessary. One suitable reagent is: $$ \text{KMnO}_4, \text{H}_2\text{SO}_4, \Delta $$ (Potassium permanganate in acidic medium with heat) Alternatively, other strong oxidizing agents can be used, such as: $$ \text{CrO}_3, \text{H}_2\text{SO}_4, \text{acetone} \quad (\text{Jones reagent}) $$ or $$ \text{Na}_2\text{Cr}_2\text{O}_7, \text{H}_2\text{SO}_4, \text{H}_2\text{O} $$ The reagent for the following conversion is: $$ \boxed{\text{KMnO}_4, \text{H}_2\text{SO}_4, \Delta \quad \text{or} \quad \text{CrO}_3, \text{H}_2\text{SO}_4, \text{acetone}} $$