A suitable reagent for distinguish between ethanoic and ethanol is

1. Analyze the question

The goal is to identify a chemical reagent that reacts differently with ethanoic acid (a carboxylic acid) and ethanol (an alcohol). We need a substance that will produce a visible change (like effervescence) with one but not the other.

2. Explain the concept

• Ethanoic acid ($CH_3COOH$): As an acid, it reacts with carbonates and hydrogen carbonates to liberate carbon(IV) oxide gas ($CO_2$). This gas causes effervescence (fizzing) when passed through limewater, turning it milky.
• Ethanol ($C_2H_5OH$): As a neutral organic compound (alcohol), it does not react with carbonates or hydrogen carbonates. Therefore, no gas is evolved.

3. Show the solution

Let's evaluate the options:

• A. Bromine water: Used to test for unsaturation (alkenes/alkynes). Neither ethanol nor ethanoic acid reacts with it under normal conditions.
• B. Fehling’s solution: Used to distinguish between aldehydes and ketones. Neither of these compounds is an aldehyde or ketone.
• C. Sodium hydrogen trioxocarbonate(IV) ($NaHCO_3$): This is a base. When added to ethanoic acid, the following reaction occurs: $CH_3COOH_{(aq)} + NaHCO_{3(s)} \rightarrow CH_3COONa_{(aq)} + H_2O_{(l)} + CO_{2(g)}$ The production of $CO_2$ gas (effervescence) confirms the presence of the acid. Ethanol does not react with $NaHCO_3$.
• D. Ammoniacal silver trioxonitrate(V) (Tollens' reagent): Used to test for aldehydes. Neither compound will give a positive "silver mirror" test.

4. Identify the answer

The correct reagent is sodium hydrogen trioxocarbonate(IV), because it reacts with the acidic group in ethanoic acid to produce bubbles of carbon(IV) oxide, while ethanol remains inert.

5. Exam Tip

Whenever you see a question asking to distinguish between an acid and another organic compound, always look for a carbonate or hydrogen carbonate in the options. These are the "gold standard" reagents for identifying carboxylic acids in JAMB Chemistry!