Aldehydes, Ketones and Carboxylic Acids quiz

The reagent used in the Etard reaction is:

Which compound does not undergo aldol condensation?

Fehling's solution is NOT reduced by:

The reagent used for Clemmensen reduction is:

Which acid is the strongest?

Which compound gives a positive iodoform test?

The Gatterman-Koch reaction converts benzene into:

Sodium ethanoate on heating with soda lime gives:

Which reagent converts a carboxylic acid into an acid chloride?

In benzoic acid, the -COOH group directs incoming electrophiles to the:

Write the equation for the Stephen reaction. (2 marks)

Give a chemical test to distinguish between propanal and propanone. (2 marks)

Why is the alpha-hydrogen of aldehydes and ketones acidic? (2 marks)

Write the equation for the cross Cannizzaro reaction or the Cannizzaro reaction of benzaldehyde. (2 marks)

How is benzoic acid prepared from toluene? Write the equation. (2 marks)

Why are carboxylic acids more acidic than phenols? (2 marks)

What is Kolbe's electrolysis? Write the equation for sodium ethanoate. (2 marks)

Write the products formed when ethanal reacts with (i) hydroxylamine and (ii) phenylhydrazine. (2 marks)

Why is sodium hydrogensulphite addition used to purify aldehydes and ketones? (2 marks)

Write the equation for the preparation of ethanoic acid using a Grignard reagent. (2 marks)

Calculate the mass of silver deposited when 1.5 g of methanal reacts with excess Tollens' reagent, given HCHO reduces 4 Ag+ ions per molecule (HCHO = 30, Ag = 108). (3 marks)

The pKa of benzoic acid is 4.19. Calculate its Ka. Calculate the degree of ionisation of 0.01 M benzoic acid using alpha = sqrt(Ka/C) (take antilog of -4.19 = 6.46 x 10^-5 and sqrt(6.46 x 10^-3) = 0.080). (3 marks)

7.2 g of butanone (C4H8O) undergoes complete Clemmensen reduction. Calculate the mass of butane formed (C = 12, H = 1, O = 16). (3 marks)

A monocarboxylic acid has a molar mass of 74 g/mol. 0.74 g of it is neutralised by how many mL of 0.1 M NaOH? Identify the acid. (3 marks)

Calculate the volume of CO2 at STP released when 4.2 g of NaHCO3 reacts with excess ethanoic acid (NaHCO3 = 84, molar volume 22.4 L). Write the equation. (3 marks)

Read the passage and answer the questions. A compound X with molecular formula C2H4O gives a silver mirror with Tollens' reagent and a red precipitate with Fehling's solution. When warmed with dilute NaOH, it gives a compound that on heating loses water to form an unsaturated aldehyde. (i) Identify X. (ii) Name the reaction with dilute NaOH and write the equations. (iii) Write the equation for its reaction with Fehling's solution. (5 marks)

Read the passage and answer the questions. Benzaldehyde has no alpha-hydrogen. When it is heated with concentrated NaOH, it gives two products. When treated with ethanal and dilute alkali, it gives cinnamaldehyde. (i) Name the reaction with concentrated NaOH and write the equation. (ii) Name the reaction with ethanal. (iii) Why can benzaldehyde not undergo self aldol condensation? (5 marks)

Read the passage and answer the questions. Vinegar contains about 6 to 8% ethanoic acid. Formic acid is found in ant stings. Chlorine substitution in ethanoic acid increases its acidity significantly. (i) Why does chlorine increase acidity? (ii) Arrange chloroethanoic acid, dichloroethanoic acid and trichloroethanoic acid in increasing order of acidity. (iii) Why is formic acid stronger than acetic acid? (5 marks)

Read the passage and answer the questions. A student wanted to convert propanone into propane. One method uses zinc amalgam and concentrated HCl; another uses hydrazine followed by heating with KOH in ethylene glycol. (i) Name the two methods. (ii) Which method suits a compound sensitive to acids? (iii) Write the equations. (5 marks)

Read the passage and answer the questions. A compound B (C3H6O2) liberates CO2 with NaHCO3. On treatment with Cl2 in the presence of red phosphorus, it gives an alpha-chloro acid. (i) Identify B. (ii) Name the reaction with Cl2 and red phosphorus. (iii) Write the equation for its reaction with NaHCO3. (5 marks)

Describe the preparation of aldehydes and ketones from alcohols, acyl chlorides, nitriles and aromatic hydrocarbons, with equations. (6 marks)

Explain the mechanism of nucleophilic addition to the carbonyl group with a diagram. Give equations for addition of HCN, NaHSO3, Grignard reagent and alcohols. (6 marks)

Describe aldol condensation, cross aldol condensation and the Cannizzaro reaction with mechanisms or equations, explaining the role of alpha-hydrogen. (6 marks)

Explain the acidity of carboxylic acids with resonance structures of the carboxylate ion. Discuss the effect of electron-withdrawing and electron-donating groups with examples. (6 marks)

Describe the chemical reactions of carboxylic acids involving cleavage of the O-H bond, C-OH bond and the -COOH group, and substitution in the hydrocarbon part, with equations. (6 marks)