Test on Carboxylic Acids

Name and give the structural formula of the second carboxylic acid [2] Functional group [1] Diagram of apparatus for preparation[8] Describe and explain the colour change as the reaction proceeds[5] Describe solubility of ethanoic acid in (a) water (b) cyclohexane and explain why in both cases. [6] When making ethanoic acid what should be in excess and why? [2]

Equation for reaction of ethanoic acid with Magnesium Equation for reaction of ethanoic acid with Magnesium? Name the organic product [5] Equation for reaction of ethanoic acid with sodium carbonate? Name the organic product. [6] What happens when ethanoic acid reacts with ethanol? Name the organic product and state what type of reaction it is. [6] How do you speed up this reaction? [4]

Ethanoic acid has a much higher boiling point than propane which has a similar RMM. Why? [4] Write equation for reaction of methanoic acid with sodium hydroxide. Name the organic product. [5] Give an equation to show what happens to ethanoic acid in dissolved in water. [4] What is meant by weak acid? [3] What does ethanoic acid do to UI? [1] Give 3 uses of carboxylic acids. [3] Why use Anti-Bumping Granules? [4]

Why use reflux? [3] Name two impurities and how to remove them. [4] Draw apparatus for extraction of ethanoic acid. Why is a water bath not used? [4] total 70

Name and give the structural formula of the second carboxylic acid [2] ethanoic acid / CH3COOH Functional group [1] - COOH Diagram of apparatus [6] layout [2] / acid+ dichromate in flask / alcohol in funnel / water bath / ABGs / water in and out / reflux / 30 mins Describe and explain the colour as the reaction proceeds[5] amber / Cr2O72- / reduced / green / Cr3+ Describe solubility of ethanoic acid in (a) water (b) cyclohexane and explain why in both cases. [6] (a) soluble / polar / C=O / water polar / insoluble / non-polar solvent When making ethanoic acid what should be in excess and why? [2] Oxidising agent / make sure it can go whole way

What happens when ethanoic acid reacts with Magnesium What happens when ethanoic acid reacts with Magnesium? Name the organic product [5] Mg + 2 CH3COOH = (CH3COO)2Mg + H2 / magnesium ethanoate What happens when ethanoic acid reacts with Sodium carbonate? Name the organic product [6] Na2CO3 + 2 CH3COOH = 2 (CH3COO)Na + CO2 + H2O / Sodium ethanoate What happens when ethanoic acid reacts with ethanol? Name the organic product and state what type of reaction it is. [6] C2H5OH + CH3COOH = CH3COOC2H5 + H2O / ethyl ethanoate / elimination / How can you speed up this reaction? [4] Use conc. / H2SO4 / as catalyst / dehydrates Ethanoic acid has a much higher boiling point than propane which has a similar RMM. Why? [3] polar / C=O / leads to dipole attraction

Write equation for reaction of methanoic acid with sodium hydroxide Write equation for reaction of methanoic acid with sodium hydroxide. Name the organic product. [5] NaOH + HCOOH = HCOONa + H2O / sodium methanoate Give an equation to show what happens to ethanoic acid in dissolved in water. [4] CH3COOH + H2O = CH3COO- + H3O+ What is meant by weak acid? [3] Only partly dissociates / in aqueous solution / pH 3 or 4 What does ethanoic acid do to Universal Indicator? [1] turns it yellow

Give 3 uses of carboxylic acids Give 3 uses of carboxylic acids. [3] condiment / solvent / preservative / cellulose acetate film / making esters Why use anti-bumping granules? [4] stop bumping / big bubbles / may damage / gives many small bubbles Why use reflux? [3] Stop volatile / reactants / escaping Name impurities and how to remove them. [4] water / anhydrous sodium sulphate / filter / ethanol / distillation / discard fraction at 800C Draw apparatus for purification. Why is a water bath not used [4] Apparatus [2] BP of Ethanoic acid 118 / BP water 100 [2] Total 77