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Class 10 Chemistry Chapter 24 Carboxylic Acids Test 2 PDF | Punjab Board 2027 Model Papers
Grade 10 Chemistry Chapter 24 Carboxylic Acids Test 2
Prepare for your Class 10 Chemistry Chapter 24: Carboxylic Acids examination with our updated Punjab Board 2027 Model Papers. This resource includes Class Test 2, Full Unit Test, and Chapter-Wise Test Series according to the new syllabus issued by PECTAA Punjab. These Chemistry practice tests help students revise important concepts, assess their preparation, and improve their performance in board examinations. Students can use these Class 10 Chemistry test papers for effective practice and revision.
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CHEMISTRYCHAPTER-24 (OBJECTIVE)CLASS TEST-2
1. During oxidation of ethanol with KMnO4 the purple colour changes to:
(a) Green(b) Brown(c) off White(d) Colourless
Ans: (d) Colourless
2. Which reagent is used to oxidize from ethanol to ethanoic acid?
(a) NaOH(b) HCl(c) Acidified KMnO4(d) Zn
Ans: (c) Acidified KMnO4
3. Which gas is evolved when ethanoic acid reacts with magnesium?
(a) Oxygen(b) Carbon dioxide(c) Nitrogen(d) Hydrogen
Ans: (d) Hydrogen
4. Which gas is evolved when ethanoic acid reacts with sodium carbonate?
(a) H2(b) O2(c) CO2(d) H2O
Ans: (c) CO2
5. Which one of the following used as a catalyst in esterification reaction?
(a) Na2CO3(b) C2H5OH(c) H2SO4(d) HNO3
Ans: (c) H2SO4
6. Ethyl acetate is used in:
(a) Antiseptic(b) Nail polish remover(c) Fuel(d) Fertilization
Ans: (b) Nail polish remover
7. Which compound is formed by the reaction of diols and dicarboxylic acids?
(a) Polyester(b) Polyamide(c) PVC(d) Polynitrides
Ans: (a) Polyester
8. Which is used as a preservative in pickles?
(a) Acetic acid(b) Benzoic acid(c) Propionic acid(d) Citric acid
Ans: (a) Acetic acid
9. Methyl butyrate gives flavour of:
(a) Apple(b) Orange(c) Pineapple(d) Banana
Ans: (a) Apple
10. Which carboxylic acid is present in Vitamin C?
(a) Citric acid(b) Ascorbic acid(c) Maleic acid(d) Acetic acid
Ans: (b) Ascorbic acid
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CHEMISTRYCHAPTER-24 (SUBJECTIVE)CLASS TEST-2
SECTION-II
i. How is ethanoic acid prepared by oxidation of ethanol? / Write the oxidation of ethanol.
Ans: Ethanol is oxidised by acidified KMnO4 (or K2Cr2O7) on heating:
CH3CH2OH + 2[O] → CH3COOH + H2O
The purple colour of KMnO4 disappears.
CH3CH2OH + 2[O] → CH3COOH + H2O
The purple colour of KMnO4 disappears.
ii. Why is oxygen supplied continuously in vinegar preparation?
Ans: The bacteria (Acetobacter) need oxygen to oxidise ethanol into ethanoic acid, so air is supplied continuously.
iii. Which conditions are required for the preparation of ethanoic acid by fermentation?
Ans: A dilute ethanol/sugar solution, Acetobacter bacteria, sufficient oxygen (air), a warm temperature (about 25–35 °C) and continuous stirring.
iv. Write a chemical reaction of acetic acid with a base.
Ans: CH3COOH + NaOH → CH3COONa + H2O (neutralization)
v. Why do carboxylic acid react with slowly with metal?
Ans: Carboxylic acids are weak acids; they ionise only partially and give few H+ ions, so they react slowly with metals.
vi. Why is acetic acid used in industry?
Ans: It is used as a solvent for lacquers and in making vinegar, dyes, plastics, rayon and other synthetic fibres.
vii. What is flavouring agents?
Ans: Substances added to food and drinks to give or improve their taste and smell. Esters are common flavouring agents.
viii. Write the important role of ester.
Ans: Esters give fruity flavours and fragrances to foods, drinks and perfumes, and are used as solvents and in making polyesters.
ix. Write the uses of acetic acid and oleic acid.
Ans: Acetic acid: vinegar, solvent, dyes and synthetic fibres. Oleic acid: making soaps, cosmetics and lubricants.
x. What are food preservatives? Give example.
Ans: Chemicals added to food to stop spoilage by bacteria and fungi. Examples: benzoic acid, sodium benzoate, citric acid.
xi. Write the application of carboxylic acid in medicine industry.
Ans: Salicylic acid is used to make aspirin (pain and fever relief); benzoic acid is used in antiseptic ointments; ascorbic acid is vitamin C.
xii. Write the name of any two esters and their flavours.
Ans: Methyl butanoate – apple; Octyl acetate – orange (also ethyl butanoate – pineapple).
SECTION-II
1. Name an oxidizing agent used to oxidize alcohols.(Ex. B. 24.2)
Ans: Acidified potassium permanganate (KMnO4) or acidified potassium dichromate (K2Cr2O7).
2. What is the role of carboxylic acids in the preparation of beverages?(Ex. B. 24.4)
Ans: Acids such as citric and carbonic acid give a sour, tangy taste and flavour to soft drinks and juices, and also act as preservatives.
