Carboxylic acids and derivatives

Which combination of substances could be used to make propyl methanoate?

Feb/March 2016

Which two compounds can combine to form an ester?

Feb/March 2017

Propanoic acid is produced naturally through bacterial fermentation of milk, and it contributes in part to the flavour of Swiss cheese. Which starting materials could be used to make propanoic acid?

Feb/March 2017

A single molecule of ammonia reacts with a single molecule of ethyl methanoate, $\text{HCO}_2\text{C}_2\text{H}_5$, giving one molecule of methanamide, $\text{HCONH}_2$, together with just one further molecule, X. When one molecule of methanamide is strongly heated, it breaks down to form one molecule of ammonia and only one additional molecule, Y. What might X and Y be?

Feb/March 2018

The structure of lactic acid is shown. Which esters could form when lactic acid is heated?

Feb/March 2018

1 mole of each of the following four compounds is reacted separately with: • an excess of sodium • an excess of sodium carbonate. Which compound gives the same volume of gas with both reagents?

Feb/March 2019

Carboxylic acids may be prepared from alcohols, nitriles or esters. Which statements are correct?

Feb/March 2019

Which reaction would form propanoic acid as one of the products?

Feb/March 2020

Compound X is exposed to an excess of lithium aluminium hydride, and the reaction is permitted to proceed to completion. What is the structure of the organic product?

Feb/March 2020

A section of the structure of strobilurin is shown. $R$ and $R'$ are inert groups. Strobilurin is heated with aqueous sulfuric acid, giving compound $X$. Compound $X$ is then reacted with hydrogen in the presence of a nickel catalyst, giving compound $Y$. What could the structure of compound $Y$ be?

Feb/March 2021

Which reaction produces butanoic acid as one of the products?

Feb/March 2021

An organic compound, T, gives no effervescence when aqueous sodium carbonate is added to it. By mass, compound T is $27.6\%$ oxygen. What could T be?

Feb/March 2021

A student proposes two uses for $\text{LiAlH}_4$. reaction 1 $\text{CH}_3\text{CH}=\text{CH}_2 \xrightarrow[]{\text{LiAlH}_4} \text{CH}_3\text{CH}_2\text{CH}_3$ reaction 2 $\text{CH}_3\text{CO}_2\text{H} \xrightarrow[]{\text{LiAlH}_4} \text{CH}_3\text{CH}_2\text{OH}$ Which of these reactions would produce the product shown?

Feb/March 2022

Compound X has a single ester group. The mass percentage of oxygen in X is 27.6%. Which pair of products could be formed on hydrolysis of X?

Feb/March 2022

Which two formulae correctly show a pair of structural isomers?

Feb/March 2023

X is an organic compound made up of carbon, hydrogen and oxygen only. The table below records the observations from three chemical tests on X. Reagent added and observation: - Na(s): effervescence - Na$_2$CO$_3$(s): effervescence - hot H$^+$/Cr$_2$O$_7^{2-}$(aq): remains orange What could be a possible structure of X?

Feb/March 2024

Compound Z is made by the reaction sequence shown below. $\text{CH}_3\text{CH}_2\text{Br}$ $\xrightarrow[\text{in ethanol}]{\text{warm with KCN}}$ compound X $\xrightarrow[\text{dilute HCl}]{\text{reflux}}$ compound Z What is the molecular formula of compound Z?

Feb/March 2024

The skeletal formulae for four organic compounds are displayed. Which two compounds, when each is heated separately with dilute sulfuric acid, produce propanoic acid as one of the products?

Feb/March 2025

The diagrams illustrate the arrangements of two isomeric dicarboxylic acids, X and Y. X may be reduced to compound P, which has empirical formula $\text{C}_2\text{H}_5\text{O}$. Y may be reduced to compound Q, which also has empirical formula $\text{C}_2\text{H}_5\text{O}$. Which statement is correct?

Feb/March 2025

When $\text{CH}_3\text{CO}_2\text{C}_3\text{H}_7$ is hydrolysed by boiling aqueous sodium hydroxide, which compound is produced?

May/June 2010

Which compound is produced when $\text{CH}_3\text{CO}_2\text{C}_3\text{H}_7$ is hydrolysed by boiling aqueous sodium hydroxide?

May/June 2010

Propanoic acid is present naturally as a product of bacterial fermentation of milk, and it contributes in part to the flavour of Swiss cheese. Which starting materials could be used to synthesise propanoic acid?

May/June 2010

Which compound is produced when $\text{CH}_3\text{CO}_2\text{C}_3\text{H}_7$ is hydrolysed by heating with aqueous sodium hydroxide?

May/June 2010

Propanoic acid is formed naturally during the bacterial fermentation of milk, and it contributes partly to the flavour of Swiss cheese. Which starting materials could be used to synthesise propanoic acid?

May/June 2010

An organic compound, $E$, has this mass composition: $\text{C}$, $48.7\%$; $\text{H}$, $8.1\%$; $\text{O}$, $43.2\%$.

May/June 2010

Acrylic acid is made from propene, a gaseous product from oil refineries. Which statement about acrylic acid is incorrect?

May/June 2011

Which formula shows an ester that produces sodium ethanoate when it is hydrolysed with aqueous sodium hydroxide?

May/June 2011

Which reaction would not produce ethanoic acid as a product?

May/June 2011

An organic compound, $X$, reacts with an excess of calcium metal to form a salt whose empirical formula is $\text{CaC}_4\text{H}_6\text{O}_4$. Which compound could $X$ be?

May/June 2011

Acrylic acid is made from propene, which is a gaseous product from oil refineries. Which statement about acrylic acid is incorrect?

May/June 2011

Which formula shows an ester that will produce sodium ethanoate when it is hydrolysed with aqueous sodium hydroxide?

May/June 2011

Ethanoic acid can react with alcohols to make esters, and an equilibrium mixture is produced. This reaction is usually done with an acid catalyst. The equation is $\text{CH}_3\text{CO}_2\text{H} + \text{ROH} \rightleftharpoons \text{CH}_3\text{CO}_2\text{R} + \text{H}_2\text{O}$.

May/June 2011

Methanoic acid, $\text{HCO}_2\text{H}$, was once called formic acid, because it occurs in ant stings and the Latin word for ant is $\textit{formica}$. John Ray first isolated it in 1671 after collecting a large number of dead ants and extracting the acid from them by distillation. In this question, all numerical answers should be given to two significant figures. At room temperature, pure methanoic acid is a liquid that is completely soluble in water. When a ‘typical’ ant stings us, a solution of methanoic acid, $A$, is injected into the skin. Solution $A$ contains 50% by volume of pure methanoic acid. A ‘typical’ ant contains $7.5 \times 10^{-6}\,\text{dm}^3$ of solution $A$.

May/June 2011

Fermenting sugars with bacteria or moulds yields many different organic compounds. One such compound found in fermented molasses is 2-ethyl-3-methylbutanoic acid, (CH$_3$)$_2$CHCH(C$_2$H$_5$)CO$_2$H, and this is what gives rum its characteristic aroma.

May/June 2011

What is the number of isomeric esters with molecular formula $\text{C}_4\text{H}_8\text{O}_2$?

May/June 2012

How many isomeric esters have the molecular formula $\text{C}_4\text{H}_8\text{O}_2$?

May/June 2012

Food additives are substances mixed into food to preserve flavour or improve taste and appearance. European Union law requires most additives used in foods to be labelled clearly in the ingredients list, either by name or by an ‘E number’. E296 is malic acid, which is found in unripe fruit. Malic acid has the structural formula $\text{HO}_2\text{CCH}_2\text{CH(OH)CO}_2\text{H}$.

May/June 2012

Lactic acid ($2$-hydroxypropanoic acid), $\text{CH}_3\text{CH(OH)CO}_2\text{H}$, is present in sour milk. Which reaction might lactic acid undergo?

May/June 2013

A sun protection cream includes the ester shown below as its active ingredient. Which substances are found among the products formed when it is hydrolysed by aqueous sodium hydroxide?

May/June 2013

The compound $Y$ has an $M_r$ of $88$. When it is added to a solution of sodium hydrogencarbonate, no fizzing occurs. It can be hydrolysed by dilute sulfuric acid to give two organic products with $M_r$ values of $46$ and $60$. What is the identity of compound $Y$?

May/June 2013

If methanoic acid is one of the two reactants used, how many isomeric esters, including structural isomers and stereoisomers, can be formed with the molecular formula $\text{C}_5\text{H}_{10}\text{O}_2$?

May/June 2013

Ethanoic acid, $\text{CH}_3\text{CO}_2\text{H}$, is an important chemical used in the industrial production of rayon and aspirin. Which processes can be used to prepare ethanoic acid?

May/June 2013

A student combined an alcohol with a carboxylic acid under suitable conditions to make an ester. A sweet-smelling organic liquid, Q, with empirical formula $\text{C}_2\text{H}_4\text{O}$ was obtained. The $M_r$ of Q was determined experimentally to be $87.5$.

May/June 2013

An ester that smells like banana has the formula $\text{CH}_3\text{CO}_2\text{CH}_2\text{CH(CH}_3)\text{CH}_2\text{CH}_3$. Which pair of reactants, under suitable conditions, would form this ester?

May/June 2014

An ester with structural formula $\text{CH}_3\text{CO}_2\text{CH}_3$ is warmed with aqueous sodium hydroxide. What are the two organic products formed in this reaction?

May/June 2014

Propanoic acid is formed naturally when milk undergoes bacterial fermentation, and it contributes partly to the characteristic taste of Swiss cheese. Which starting materials could be chosen to prepare propanoic acid?

May/June 2014

Diesters may be prepared from diacids such as propane-1,3-dioic acid, $\text{HO}_2\text{CCH}_2\text{CO}_2\text{H}$. Which pair of reactants would produce the diester $\text{CH}_3\text{CH}_2\text{OCOCH}_2\text{CH}_2\text{CO}_2\text{CH}_2\text{CH}_3$?

May/June 2014

Which compounds give propanoic acid after hydrolysis with dilute sulfuric acid?

May/June 2014

Which organic product is obtained when ethanamide, $\text{CH}_3\text{CONH}_2$, is boiled with excess aqueous sodium hydroxide?

May/June 2015

An organic compound, X, reacts with calcium metal to form a salt whose empirical formula is $\text{CaC}_4\text{H}_4\text{O}_4$. What might X be?

May/June 2015

5-hydroxypentanoic acid is easily changed into the cyclic compound L. Which of the following statements about this reaction are correct?

May/June 2015

Sirolimus is a drug administered to patients following kidney transplants. When Sirolimus reacts with hot aqueous sodium hydroxide, an equimolar mixture of two organic products is formed. What is the structural formula of the product with the lower relative molecular mass?

May/June 2015

Monopotassium citrate is used as an emulsifying agent in powdered milk and in powdered soups. Its formula is shown below. Which of the following statements about monopotassium citrate are correct?

May/June 2015

Compound X, $\text{C}_5\text{H}_{12}\text{O}$, undergoes oxidation with acidified sodium dichromate(VI) to form compound Y. Compound Y is then reacted with butan-2-ol, with a small amount of concentrated sulfuric acid present, to produce liquid Z. Give one possible formula for Z.

May/June 2015

The structural formula for compound X is illustrated below. Identify the name of compound X and state how its boiling point compares with that of butanoic acid?

May/June 2016

Cyclic esters are referred to as lactones. Delta lactone is used both as a solvent and in producing polyesters. From which compound could delta lactone be formed in a single reaction?

May/June 2016

The ester $\text{CH}_3\text{CH}_2\text{CH}_2\text{CO}_2\text{CH}_2\text{CH(CH}_3)_2$ underwent hydrolysis in acidic conditions. What organic products are formed in this hydrolysis?

May/June 2016

A small quantity of water is added to each of the compounds below, and the mixture is warmed. Which compounds will produce an acidic gas?

May/June 2016

How many isomeric esters, counting structural isomers and stereoisomers, can be formed with the molecular formula $\text{C}_5\text{H}_{10}\text{O}_2$, if methanoic acid is one of the two reactants used?

May/June 2016

Compound X, $\text{C}_4\text{H}_8\text{O}_2$, contains a straight carbon chain. An aqueous solution of X has an approximate pH of 3. Compound Y, $\text{C}_3\text{H}_8\text{O}$, is a secondary alcohol. X and Y are mixed and reacted in the presence of a small amount of concentrated sulfuric acid to produce Z as the main organic product. Which structural formula represents Z?

May/June 2016

A pineapple-smelling ester may be prepared in the laboratory from butanal by means of this reaction scheme. $\text{CH}_3(\text{CH}_2)_2\text{CHO} \xrightarrow{\text{NaBH}_4} X$ $\text{CH}_3(\text{CH}_2)_2\text{CHO} \xrightarrow{\text{Cr}_2\text{O}_7^{2-}/\text{H}^+} Y$ $X$ and $Y$ react together in the presence of concentrated $\text{H}_2\text{SO}_4$ to produce an ester. What is the structural formula for this ester?

May/June 2016

The ester, $\text{CH}_3\text{CH}_2\text{CO}_2\text{CH}_3$, is broken down by boiling it with aqueous sodium hydroxide. What compound is one of the products?

May/June 2016

A sequence of reactions is displayed.

May/June 2016

This question concerns molecules that have molecular formula $\text{C}_4\text{H}_8\text{O}_2$.

May/June 2016

Lactide is an intermediate used in the production of a synthetic fibre. Which compound can form lactide when heated with an acid catalyst?

May/June 2017

Citral is present in lemongrass oil. It may react to form compound W. Citral $\xrightarrow[\text{an excess of }\text{H}_2/\text{Ni}]{}$ V $\xrightarrow[\text{hot, concentrated acidified manganate(VII) under reflux}]{}$ W What might compound W be?

May/June 2017

Which of these statements about ethanol and ethanoic acid are correct?

May/June 2017

A carboxylic acid, P, cannot form any chain isomers. It reacts with an alcohol, Q, which has only one positional isomer. What ester could be produced by a reaction between P and Q?

May/June 2017

Which compound is chiral and reacts with $\text{Na}_2\text{CO}_3$ to produce $\text{CO}_2$?

May/June 2017

When hydrolysed, which compound produces propanoic acid together with propan-2-ol?

May/June 2017

Carboxylic acids can be made by a number of different routes. In which reaction would propanoic acid be produced?

May/June 2017

Chlorogenic acid occurs in green coffee beans and is used in weight-loss treatments. Which product is obtained in good yield when chlorogenic acid is reacted with an excess of sodium carbonate solution at room temperature? ($R = \text{C}_5\text{H}_9\text{O}_2$ and does not take part in the reaction with sodium carbonate.)

May/June 2017

How many esters having the molecular formula $\text{C}_5\text{H}_{10}\text{O}_2$ can be prepared by reacting a primary alcohol with a carboxylic acid?

May/June 2017

Ethyl propanoate is heated under reflux with aqueous sodium hydroxide. The alcohol formed is then reacted with methyl propanoic acid to produce a second ester. What is the structural formula for this second ester?

May/June 2018

Four reactions of propanoic acid that produce salts and other products are shown. Which reaction does not display the formulae for all of the correct products?

May/June 2018

Ethanal, $\text{CH}_3\text{CHO}$, is used in the preparation of product R by means of a three-stage synthesis. $\text{CH}_3\text{CHO} \xrightarrow[\text{NaCN}]{\text{HCN}} \text{product P} \xrightarrow[\text{reflux}]{\text{H}_2\text{SO}_4\text{(aq)}} \text{product Q} \xrightarrow[\text{a few drops}]{\text{conc. }\text{H}_2\text{SO}_4} \text{product R}$ In the reaction, two molecules of Q combine to form one molecule of R and two molecules of water. Each molecule of R contains two ester functional groups. Sodium does not react with R. Determine the empirical formula of R.

May/June 2018

The ester ethyl butanoate may be hydrolysed with excess dilute sodium hydroxide solution. Which substance is formed in this reaction?

May/June 2018

Several different reactions can produce carboxylic acids. Which of the statements below are correct?

May/June 2019

The diagram indicates that a carboxylic acid P can be made from X, Y or Z. Which row is the correct one?

May/June 2019

Which two substances could react to produce the ester $\text{CH}_3\text{CH}_2\text{CO}_2\text{CH}_3$?

May/June 2019

An ester is shown. What structure would the carboxylic acid have that is produced when the ester linkage undergoes acid hydrolysis?

May/June 2019

An organic molecule $X$ has the molecular formula $\text{C}_5\text{H}_{10}\text{O}_2$. Its infra-red spectrum shows a strong peak at $1250\,\text{cm}^{-1}$, another strong peak at $1720\,\text{cm}^{-1}$, but no strong peak above $3100\,\text{cm}^{-1}$. Which one of the following compounds could $X$ be?

May/June 2019

A number of esters found naturally are used as flavourings in food.

May/June 2019

If compound X is heated under reflux with aqueous sodium hydroxide solution, the products obtained are sodium ethanoate and hexan-1-ol. Which compound is X?

May/June 2020

The structure of compound X is displayed. X is reacted separately with NaOH(aq) and LiAlH$_4$ to produce Y and Z. Identify Y and Z.

May/June 2020

Ester X is displayed. Ester X: CH$_3$CO$_2$(CH$_2$)$_7$CH$_3$ Ester X is hydrolysed in aqueous sodium hydroxide. What is the molecular formula of one of the products?

May/June 2020

What is the total number of isomeric esters for the molecular formula $\text{C}_4\text{H}_8\text{O}_2$?

May/June 2020

The structural formula of ester P is shown here. Which compounds are formed when P undergoes hydrolysis with dilute hydrochloric acid?

May/June 2020

The compound cetyl palmitate, $\text{C}_{15}\text{H}_{31}\text{CO}_2\text{C}_{16}\text{H}_{33}$, is a wax-like solid. Cetyl palmitate is warmed under reflux with an excess of aqueous sodium hydroxide. Which products are formed?

May/June 2021

Propanoic acid is made to react with an excess of lithium aluminium hydride. The organic compound obtained from this reaction is then reacted with ethanoic acid, with concentrated sulfuric acid present, to produce product X. What are the main commercial applications of X? 1 for fuel 2 as a solvent 3 for flavouring

May/June 2021

Which of the following mixtures produces a carboxylic acid as one of the products?

May/June 2021

Compound Y is reacted with one reagent in suitable conditions. The product formed is 2-methylbutanoic acid. What might compound Y be?

May/June 2021

Ethanedioic acid, $\mathrm{HO_2CCO_2H}$, has a relative molecular mass of $90.0$.

May/June 2021

Aqueous bromine reacts with methanoic acid to produce hydrogen bromide and carbon dioxide gas. $\text{Br}_2(aq) + \text{HCO}_2\text{H}(aq) \rightarrow 2\text{HBr}(aq) + \text{CO}_2(g)$ The table gives the oxidation numbers of bromine and carbon in the species taking part in this reaction.

May/June 2021

Compound $X$ has the same functional groups as citric acid. The table sets out a few similarities and differences between citric acid and compound $X$.

May/June 2021

How many esters have molecular formula $\text{C}_4\text{H}_8\text{O}_2$?

May/June 2022

Which compound gives butan-2-ol and ethanoic acid when it is hydrolysed?

May/June 2022

Ethyl butanoate is used as a flavouring and has a fruity taste. Which row is the correct one?

May/June 2022

An ester is displayed. Which two compounds combine to produce this ester?

May/June 2022

Which compound can be converted into propanoic acid using a single reagent?

May/June 2022