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Class 12 Chemistry talks about Aldehydes, Ketones, and Carboxylic Acids. This chapter tells us about how that compound form they are made, and how it reacts. These carbonyl compounds are really important in both our day-to-day life and industries. For instance, aldehydes and ketones are common in perfumes, medicines, and food preservatives. Carboxylic acids, such as acetic acid and citric acid, are common organic acids we come across in daily life.
NCERT solutions for class 12 of chapter 8 cover essential reactions like nucleophilic addition, oxidation, and reduction, which are crucial for grasping organic chemistry. The NCERT solutions offer straightforward explanations and step-by-step answers to help students understand the material and prepare for tests with confidence.
Also Read,
NCERT Exemplar Solutions For Aldehydes, Ketones and Carboxylic Acid |
Aldehydes Ketones and Carboxylic Acid NCERT Chapter Notes |
Page no. 231
Q 8.1(i) Write the structures of the following compounds.
Answer :
The structure of the compound
Q8.1(ii) Write the structures of the following compounds.
Answer :
The structure of the compound 3-Hydroxy butanal is shown here-
Q8.1(iii) Write the structures of the following compounds.
2-Hydroxy cyclopentane carbaldehyde
Answer :
The structure of the compound 2-Hydroxycyclopentane carbaldehyde is shown here-
Q 8.1(iv) Write the structures of the following compounds.
Answer :
The structure of the compound 4-oxopentanal is shown here-
Q8.1(v) Write the structures of the following compounds.
Answer :
The structure of the compound Di-sec. butyl ketone is shown here-
Q8.1(vi) Write the structures of the following compounds.
Answer :
The structure of the compound 4-Fluoro acetophenone is shown here-
Page no.234
Q 8.2(i) Write the structures of products of the following reactions:
(i)
Answer :
When benzene is treated with acid chloride in the presence of anhydrous aluminum chloride
Q8.2(ii) Write the structure of products of the following reactions;
(ii)
Answer :
Reaction of acyl chloride with dialkylcadmium (
Q8.2(iii) Write the structures of products of the following reactions:
(iii)
Answer :
When propyne reacts with
Q8.2(iv) Write the structures of products of the following reactions:
(iv)
Answer :
Chromyl chloride oxidise the methyl group into a chromium complex, which on hydrolysis give aldehyde group.
Page no. 236
Q8.3 Arrange the following compounds in increasing order of their boiling points.
Answer :
Increasing order in their boiling points-
Alcohol has the highest boiling point due to more extensive intermolecular H-bonding. Aldehyde is more polar than ether so, ethanal has high BP than ethyl ether. And alkane has the lowest BP.
Page no. 243
Ethanal, Propanal, Propanone, Butanone.
Answer :
By the above structure, we can see that, due to +I effect of alkyl group te electron density at Carbonyl carbon increase from ethanal to bytanone. And so the tendency of attacking nucleophile is decreased.
Thus the increasig order (reactivity towards nucleophile)-
Butanone < propanone < propanal < ethanal
Benzaldehyde, p-Tolualdehyde, p-nitrobenzaldehyde, Acetophenone.
Answer :
If +I effect is more its reactivity towards nucleophilic addition is less. and -I is more, more reactive toward addition.
So, according to this concept, increasing order of their reactivity in nucleophilic addition reactions-
Acetophenone < p-tolualdehyde < benzaldehyde <p-nitrobenzaldehyde
Q8.5(i) Predict the products of the following reactions:
(i)
Answer :
The product of the reaction is-
Water molecule is removed as a by-product in this reaction.
Q 8.5(ii) Predict the products of the following reactions:
(ii) →
Answer :
The product of the reaction is a hydrazone, which is formed when ketone and 2, 4-dinitrophenyl hydrazine derivative reacts with each other.
Q 8.5(iii) Predict the products of the following reactions:
Answer :
The product of the above reaction is -
Water molecule is eleminated as a by-product in this reaction
Q8.5(iv) Predict the products of the following reactions:
(iv)
Answer :
The product of the above reaction is -
water is also obtained in this reaction as a by-product
Q 8.6(i) Give the IUPAC names of the following compounds:
Answer :
The IUPAC name of the compound
3-phenyl propanoic acid
Q8.6(ii) Give the IUPAC names of the following compounds:
Answer :
The IUPAC name of the compound
3-methyl but-2-en-1-oic acid
Q 8.6(iii) Give the IUPAC names of the following compounds:
Answer :
The IUPAC name of the compound is-
2-methyl cyclopentane carboxylic acid
Q8.6(Iv) Give the IUPAC names of the following compounds:
(iv)
Answer :
The IUPAC name of the compound is-
2, 4, 6-trinitrobenzoic acid
Page no. 248
Q8.7(i) Show how each of the following compounds can be converted to benzoic acid?
Answer :
Strong oxidising agents like potassium permanganate in the presence of KOH, followed by acidic hydrolysis give benzoic acid.
Q 8.7(ii) Show how each of the following compounds can be converted to benzoic acid.
Answer :
On strong oxidation with potassium permanganate in presenc of KOH followed by acidic hydrolysis, give benzoic acid
Q 8.7(iii) Show how each of the following compounds can be converted to benzoic acid?
Answer :
Make bromobenzene first Grignard reagent, react it with dry ice (carbon dioxide) followed by acidic hydrolysis gives benzoic acid.
Q 8.7(iv) Show how each of the following compounds can be converted to benzoic acid?
Answer :
On strong oxidation with potassium permanganate (
Page no. 254
Q8.8(i) Which acid of each pair shown here would you expect to be stronger?
Answer :
Q8.8(ii) Which acid of each pair shown here would you expect to be stronger?
Answer :
Fluorine has more -I effect than chlorine. So,
Q8.8(iii) Which acid of each pair shown here would you expect to be stronger?
(iii)
Answer :
Since we know that inductive effect depends on distance. Greater is the distance lesser is the effect. So, -I effect in
Q 8.8(iv) Which acid of each pair shown here would you expect to be stronger?
Answer :
Due to -I effect of Fluorine in A, it is easy to release proton (
Q 8.1 (i). What is meant by the following terms ? Give an example of the reaction in each case.
Answer:
Cyanohydrin -
When ketone and aldehyde react with the hydrogen cyanide (
Q 8.1 (ii). What is meant by the following terms? Give an example of the reaction in each case.
Answer:
Acetal -
When aldehyde reacts with one molecule of monohydric alcohol in presence of dry HCl, it gives intermediate compound known as hemiacetals, which on further reaction with one more molecule of alcohol gives a product (gem-dialkoxy compound), known as acetal.
For example:
Q 8.1(iii). What is meant by the following terms? Give an example of the reaction in each case.
Answer:
Semicarbazone -
This is the derivative of the aldehyde and ketone and it is derived from the condensation reaction between aldehyde and ketone. For example:
Q 8.1(iv). What is meant by the following terms? Give an example of the reaction in each case.
Answer:
Aldol -
For example:
Q 8.1(v) What is meant by the following terms? Give an example of the reaction in each case.
Answer:
Hemiacetal -
Aldehyde reacts with one equivalent of a monohydric alcohol, to yield an alkoxy alcohol intermediate compound, in presence of dry hydrochloric acid. The intermediate is called hemiacetal.
For example:
Q 8.1 (vi) What is meant by the following terms? Give an example of the reaction in each case.
Answer:
Oxime -
Aldehyde and ketone on reacting with the hydroxylamine in a weakly basic medium give oximes.
The general form of oxime-
For example:
Q8.1 (vii) What is meant by the following terms? Give an example of the reaction in each case.
Answer:
Ketal-
It is a cyclic compound, which is formed when a ketone reacts with the ethylene glycol in the presence of dry hydrochloric acid.
For example:
Q 8.1(vii) What is meant by the following terms? Give an example of the reaction in each case.
Answer:
Imine -
These are the chemical compounds having carbon-nitrogen double bonds. It is formed when aldehyde and ketone react with ammonia and its derivatives.
For example:
Q 8.1(ix) What is meant by the following terms? Give an example of the reaction in each case.
Answer:
2,4-DNP-derivative-
These are produced when aldehyde and ketone are reacted with the 2, 4-dinitrophenylhydrazine in a weak basic medium. 2, 4DNP test is used for distinguishing between aldehyde and ketone.
For example:
Q 8.1 (x) What is meant by the following terms? Give an example of the reaction in each case.
Answer:
Schiff’s base-
When aldehyde and ketone are treated with the primary aliphatic or aromatic amines in the presence of acid produces Schiff's base.
For example:
Q 8.2(i) Name the following compounds according to IUPAC system of nomenclature:
Answer:
IUPAC name of this compound is 4-methyl pentanal
Q 8.2(ii) Name the following compounds according to IUPAC system of nomenclature:
Answer:
The IUPAC name of the compound is 6-chloro-4ethyl hexane-3-one
Q8.2(iii) Name the following compounds according to IUPAC system of nomenclature:
Answer:
The structure of the compound is
The IUPAC name of the compound is But-2-en-1-al
Q8.2(iv) Name the following compounds according to IUPAC system of nomenclature:
Answer:
The structure of the given compound is-
The IUPAC name of the compound is pentan-2, 4-dione.
Q8.2 (v) Name the following compounds according to IUPAC system of nomenclature:
Answer:
The structure of the compound is -
The IUPAC name of the given compound is 3, 3, 5-trimethyl hexan-2-one.
Q8.2 (vi) Name the following compounds according to IUPAC system of nomenclature:
Answer:
The structure of the compound is -
The IUPAC name of the compound is 3, 3-dimethyl butanoic acid .
Q8.2 (vii) Name the following compounds according to IUPAC system of nomenclature:
Answer:
The structure of the compound is-
The IUPAC name of the compound is Benzene-1, 4-dicarbaldehyde.
Q8.3(i) Draw the structures of the following compounds.
Answer:
The structure of the 3-methylbutanal is shown here-
Q8.3 (ii) Draw the structures of the following compounds.
Answer:
The structure of p-nitro propiophenone is shown here-
Q8.3 (iii) Draw the structures of the following compounds.
Answer:
The strcuture of the
Q8.3(iv) Draw the structures of the following compounds.
Answer:
The structure of the compound 4-methylpent-3-en-2-one is shown here-
Q8.3(v) Draw the structures of the following compounds.
Answer:
The structure of the compound 4-chloro-pentan-2-one is shown here-
Q8.3 (vi) Draw the structures of the following compounds.
3-Bromo-4-phenylpentanoic acid
Answer:
The structure of the compound 3-Bromo-4-phenyl pentanoic acid is shown here-
Q8.3 (vii) Draw the structures of the following compounds.
Answer:
The structure of the compound p,p’-dihydroxy benzophenone acid is shown here-
Q8.3 (viii) Draw the structures of the following compounds.
Answer:
The structure of the compound Hex-2-en-4-ynoic acid acid is shown here-
Answer:
The structure of the compound is
The IUPAC name of the compound is hept-2-one Common name is methyl-n-propyl ketone
Answer:
The structure of the compound is
The IUPAC name of the compound is 4-bromo-2-methylhexanal
The common name is -
Answer:
structure os the compound is
The IUPAC name of the compound is heptanal
Answer:
structur eof the compound is
The IUPAC name of the sompound is 3-phenylprop-2-ene-al
Common name is
Answer:
The IUPAC name of the compound is cyclopentane carbaldehyde.
Answer:
structure of the compound is
The IUPAC name of the compound is Diphenyl mentanone.
The common name is - benzophenone
Q8.5 (i) Draw structures of the following derivatives.
The 2,4-dinitro phenyl hydrazone of benzaldehyde
Answer:
The structure of 2,4-dinitro phenyl hydrazone of benzaldehyde
Q8.5 (ii) Draw structures of the following derivatives.
Answer:
The structure of the Cyclopropanone oxime
Q 8.5 (iii) Draw structures of the following derivatives.
Answer:
The structure of Acetaldehyde dimethylacetal
Q 8.5 (iv) Draw structures of the following derivatives.
The semicarbazone of cyclobutanone
Answer:
The structure of the semicarbazone of cyclobutanone
Q8.5 (v) Draw structures of the following derivatives.
The ethylene ketal of hexan-3-one
Answer:
The structure of the ethylene ketal of hexan-3-one
Q8.5 (vi) Draw structures of the following derivatives.
The methyl hemiacetal of formaldehyde
Answer:
The structure of the compound methyl hemiacetal of formaldehyde
Q 8.6 (i) Predict the products formed when cyclohexane carbaldehyde reacts with following reagents.
Answer:
When cyclohexane carbaldehyde reacts with
Q 8.6 (ii) Predict the products formed when cyclohexane carbaldehyde reacts with the following reagents.
Answer:
Structure of cyclohexanecarbaldehyde
Cyclohexanecarbaldehyde reacts with Tollen's reagent and reduces it to silver (
So the reaction is-
Q 8.6 (iii) Predict the products formed when cyclohexane carbaldehyde reacts with following reagents.
Answer:
Structure of cyclohexanecarbaldehyde
The reaction of cyclohexane carbaldehyde with semicarbazide and weak acid is-
The
Q 8.6 (iv) Predict the products formed when cyclohexane carbaldehyde reacts with following reagents.
Answer:
Structure of cyclohexanecarbaldehyde
reaction of cyclohexanecarbaldehyde with an excess of ethanol and acid to form cyclohexanecarbaldehyde diethyl acetal.
Q 8.6 (v) Predict the products formed when cyclohexane carbaldehyde reacts with following reagents.
Zinc amalgam and dilute hydrochloric acid
Answer:
Structure of cyclohexane carbaldehyde
When cyclohexane carbaldehyde reacts with zinc amalgam(
Q 8.7 (i) Which of the following compounds would undergo aldol condensation, the Cannizzaro reaction, and which neither? Write the structures of the expected products of aldol condensation and Cannizzaro reaction.
Methanal
Answer:
The compounds of ketones or aldehydes having at least one
The products of the reactions are, in which one product is reduced and another is oxidised to a carboxylic acid salt-
Answer:
In 2-methylpentanal, there is one alpha-hydrogen atom, so it gives an aldol condensation reaction. Hence aldol product is-
Answer:
Benzaldehyde Structure
In this structure, we can clearly see that there is no alpha-hydrogen atom. So, it gives the Cannizzaro reaction.
Answer:
It does not give any of reaction because it is a keto compound and has no alpha-hydrogen atom. Hence, it does not give the Cannizzaro as well as the aldol reaction.
Structure -
Answer:
Yes, this compound will give an aldol condensation reaction due to the presence of an alpha-hydrogen atom. Two moles of cyclohexanone react with each other in which one molecule act as a nucleophile and the other act as an electrophile.
Answer:
1-Phenylpropanone has two alpha-hydrogen atoms, so it gives an aldol condensation reaction. It reacts with another molecule of 1-Phenylpropanone in the presence of dil.
Answer:
Phenylacetaldehyde it has two alpha-hydrogens, which makes it possible to perform the aldol condensation reaction. So, the reaction is shown here;
Answer:
It does not give any of the reactions, either the aldol reaction or Cannizzaro reaction, because it is an alcohol.
Answer:
In this compound, there is no alpha hydrogen, which means it gives the Cannizzaro reaction in the presence of conc. sodium hydroxide (
Q 8.8 (i) How will you convert ethanal into the following compounds?
Answer:
On treating ethanal with dil. alkali it gives 3-hydroxybutanal, which on further reduction with
Q8.8 (ii) How will you convert ethanal into the following compounds?
Answer:
On treating with he presence of dil. alkali (
Q 8.8 (iii) How will you convert ethanal into the following compounds?
Answer:
When the given substrate is reacting with the tollens reagent, it produces but-2-enoic acid.
Answer:
Propanal -
butanal -
In cross-aldol condensation, there are a total of four cases of reaction-
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Answer:
According to the given information, the molecular formula is
Hence, the structure of the compound (2-ethylbenzaldehyde) is-
By following the reaction we can understand this problem-
Q 8.12 (i) Arrange the following compounds in increasing order of their property as indicated:
Acetaldehyde, Acetone, Di-tert-butyl ketone, Methyl tert-butyl ketone (reactivity towards HCN)
Answer:
Increasing order (reactivity towards HCN)-
Di-tert-butyl ketone < Methyl tert-butyl ketone < Acetone < Acetaldehyde
The attacking power of
By observing the structure of all compounds, we can arrange them in order to reactivity towards HCN.
Q 8.12 (ii) Arrange the following compounds in increasing order of their property as indicated:
Answer:
increasing order of their acidic strength-
Due to the presence of Bromine, which shows -I effect, and we know that -I grows weaker as distance increases. And in case of n-propyl and isopropyl, the +I effect is more in isopropyl, so it is weaker in acidic strength.
Q 8.12 (iii) Arrange the following compounds in increasing order of their property as indicated:
Benzoic acid, 4-Nitrobenzoic acid, 3,4-Dinitrobenzoic acid, 4-Methoxybenzoic acid (acid strength)
Answer:
Increasing order of acidic strength -
4-methoxybenzoic acid < Benzoic acid < 4-Nitrobenzoic acid < 3,4-Dinitrobenzoic acid
As we know, electron-withdrawing groups increase the strength of the acid, and electron-donating groups decrease the strength of the acid. Therefore, 4-methoxybenzoic acid is the weakest acid among them, and 3,4-Dinitrobenzoic acid is the strongest due to the presence of 2 electron-withdrawing groups and then by 4-nitrobenzoic acid.
Q 8.13 (i) Give simple chemical tests to distinguish between the following pairs of compounds.
Answer:
Both compounds can be distinguished by the following tests-
Propanal reduces the Tollens reagent, but propanone does not.
Acetaldehyde responds to Fehling's test, but ketone does not. So, Propanal gives a positive Fehling's test but not propanone.
Q 8.13 (ii) Give simple chemical tests to distinguish between the following pairs of compounds.
Answer:
Acetophenone gives a positive iodoform test; it reacts with
benzophenone +
Q 8.13 (iii) Give simple chemical tests to distinguish between the following pairs of compounds.
Answer:
Phenol gives ferric chloride test (
Q 8.13 (iv) Give simple chemical tests to distinguish between the following pairs of compounds.
Benzoic acid and Ethyl benzoate
Answer:
Both can be distinguished by the sodium bicarbonate test. In this test, benzoic acid reacts with
Q8.13 (v) Give simple chemical tests to distinguish between the following pairs of compounds.
Answer:
They can be distinguished by the iodoform test,
This test is given by compounds having a methyl ketone group. So, pentan-2-one gives this test, and pentan-3-one does not.
Q 8.13 (vi) Give simple chemical tests to distinguish between the following pairs of compounds.
Answer:
Both can be distinguished by
Q 8.13 (vii) Give simple chemical tests to distinguish between the following pairs of compounds.
Answer:
Ethanal and Propanal can be distinguished by the Iodoform test.
Ethanal has one methyl group attached to the Carbonyl group, so it gives a positive iodoform test, but propanal does not give this test.
Answer:
Benzene, on bromination, formed bromobenzene, and after that, we have to react with
Answer:
Benzene on bromination, formed bromobenzene, and after that, we have to react with
Answer:
By friedel craft alkylation of benzene give methyl benzene, which on nitration give meta and para substituted methyl benzene, para substituted is major product. Oxidation of para substituted methyl benzene(
Answer:
Alkylation of benzene in presence of anhydrous
Answer:
Alkylation of benzene gives toluene, which on further reaction with
Q 8.15(i) How will you bring about the following conversions in not more than two steps?
Answer:
First, reduce propanone with the help of lithium aluminum hydride (
Q 8.15(ii) How will you bring about the following conversions in not more than two steps?
Answer:
First react it with
Q 8.15 (iii) How will you bring about the following conversions in not more than two steps?
Answer:
Ethanol on heating at 573K in the presence of copper it converts into ethanol, and then by aldol condensation, we get 3-hydroxybutanal.
Q 8.15 (iv) How will you bring about the following conversions in not more than two steps?
Benzene to m-nitroacetophenone
Answer:
Benzene, on reacting with acetic anhydride
Q 8.15 (v) How will you bring about the following conversions in not more than two steps?
Answer:
On oxidation of benzaldehyde, it converted into benzoic acid, which on further reacting with
Q 8.15 (vi) How will you bring about the following conversions in not more than two steps?
Bromobenzene to 1-phenylethanol
Answer:
Bromobenzene on reacting with
Q 8.15 (vii) How will you bring about the following conversions in not more than two steps?
Benzaldehyde to 3-Phenylpropan-1-ol
Answer:
BY cross aldol condensation of benzaldehyde and acetaldehyde gives 3-phenylprop-2-ene-al, which on catalytic hydrogenation gives 3-Phenylpropan-1-ol
Q 8.15 (viii) How will you bring about the following conversions in not more than two steps?
Benzaldehyde to α-hydroxy phenyl acetic acid
Answer:
Nucleophilic reaction of benzaldehyde with
Q 8.15(ix) How will you bring about the following conversions in not more than two steps?
Benzoic acid to m-nitrobenzyl alcohol
Answer:
On nitration of benzoic acid gives meta-substituted nitrobenzoic acid, which, on further reacting with a reducing agent and followed by acidic hydrolysis, gives nitrobenzyl alcohol.
Q 8.16 (i) Describe the following.
Answer:
Acetylation-
The addition of an acetyl functional group (
Q 8.16 (ii) Describe the following.
Answer:
Cannizzaro reaction-
Aldehydes that do not have any alpha-hydrogen undergo self-oxidation as well as reduction reaction on treatment with concentrated alkalis. In this reaction, one molecule gets reduced and the other is oxidised to a carboxylic acid salt.
Q 8.16 (iii) Describe the following.
Answer:
Cross aldol condensation -
In aldol condensation, if the reactants are two different aldehydes or ketones, then it is called cross-aldol condensation. If both of the reactants contain alpha-hydrogen atoms, then it gives a mixture of four products.
Q 8.16 (iv) Describe the following.
Answer:
Decarboxylation -
The reaction in which the carboxylic acid loses carbon dioxide to hydrocarbon, in the presence of sodalime(
Q 8.17(i) Complete each synthesis by giving missing starting material, reagent or products.
Answer:
Potassium permanganate oxidizes the substituted ethyl group to
Q 8.17(ii) Complete each synthesis by giving the missing starting material, reagent, or products.
Answer:
The -OH groups of both carboxylic acid is replaced by the chlorine
So, the overall reaction is
Q 8.17 (iii) Complete each synthesis by giving the missing starting material, reagent, or products
Answer:
In this reaction, the
So, the final product is-
Q8.17(iv) Complete each synthesis by giving the missing starting material, reagent or products.
Answer:
Benzene reacts with benzoyl chloride in the presence of anhydrous aluminium chloride (
Q 8.17(v) Complete each synthesis by giving the missing starting material, reagent or products.
Answer:
Since the given reactant is an aldehyde compound, it gives a positive Tollens' test by reducing the Tollens reagent.
Q 8.17 (vi) Complete each synthesis by giving missing starting material, reagent or products.
Answer:
In this reaction, the nucleophile CN attacks on -CHO group because it has more reactivity towards
So the reaction gives
Q8.17 (vii) Complete each synthesis by giving the missing starting material, reagent, or products.
Answer:
The given reaction is a cross aldol reaction between benzaldehyde and propanal in the presence of dil. sodium hydroxide
Q 8.17 (viii) Complete each synthesis by giving the missing starting material, reagent, or products.
Answer:
In this reaction
Q8.17(ix) Complete each synthesis by giving the missing starting material, reagent, or products.
Answer:
Q 8.17(x) Complete each synthesis by giving the missing starting material, reagent, or products.
Answer:
Diborane reacts with an alkene to give trialkyl boranes (addition product), and this is oxidised to alcohol by using hydrogen peroxide.
After the pyridinium chlorochromate (PCC) is reacted with alcohol to convert it into an Aldehyde group.
Q 8.17 (xi) Complete each synthesis by giving the missing starting material, reagent or products.
Answer:
The above reaction is ozonolysis reaction in which ozone molecule breaks the double bond of the alkene and formed a ketone or aldehyde as a product.
Q 8.18(i) Give plausible explanation for each of the following:
Cyclohexanone forms cyanohydrin in good yield but 2,2,6-trimethylcyclohexanone does not.
Answer:
Structure of 2,2,6-trimethylcyclo hexanone
Cyclohexanone forms cyanohydrin when the nucleophile (
In this case, there is less hindrance around the CO group so the nucleophile can attack easily. But in case of 2,2,6-trimethylcyclo hexanone at the alpha (
Q 8.18(ii) Give plausible explanation for each of the following:
Answer:
In Semicarbazide,
One of the
Q 8.18(iii) Give a plausible explanation for each of the following:
Answer:
If either water or the ester is not removed immediately, then the ester can react with water and again and give back the reactants.
Thus, to shift the reaction in the forward direction, we need to produce more ester or remove either of the two.
Answer:
In the question, it is given that,
% of carbon = 69.77
% of Hydrogen = 11.63
% of Oxygen = (100-69.77-11.63) = 18.6
Now, the no. of moles of the components are-
Thus ration of C:H:O = 5.81:11.63:1.16
To get empirical formula we need to divide them by 1.16 .So,
C:H:O= 5:10:1
So, the empirical formula is
The molecular mass of the compound =
Since the compound does not give tollens test it means it is not an aldehyde. It is given that, the compound gives positive iodoform test it means the compound must be methyl ketone.
On oxidation, it gives ethanoic acid and propanoic acids. Therefore, the compound should be
Pentan-2-one
the structure of the compound is -
Answer:
In the carboxylate ion, the electron is delocalised between the oxygen, which is electronegative in nature. But in the case of phenoxide ion, the electrons are delocalised between the less electronegative atom, and also phenoxide ion has non-equivalent resonance structures. Therefore,the carboxylate ion is more resonance stable than the phenoxide ion, and we know that the more stable the conjugate base of an acid, high stronger is the acid
Question.
Consider the above reaction sequence and identify the major product P.
(1) Methane
(2) Methanal
(3) Methoxymethane
(4) Methanoic acid
Answer.
Hence, the correct answer is option (1).
Question. Fehling’s solution ‘A’ is:
(1) aqueous copper sulphate
(2) alkaline copper sulphate
(3) alkaline solution of sodium potassium tartrate (Rochelle’s salt)
(4) aqueous sodium citrate
Answer: Fehling's solution A is a deep blue aqueous solution of copper(II) sulfate. It's also known as cupric sulfate, blue vitriol, or bluestone.
Fehling solution ‘A’ = Aqueous copper sulphate
Fehling solution ‘B’ = Alkaline sodium potassium tartrate (Rochelle salt)
Hence, the correct answer is option (1).
NCERT Solutions for Class 12 Chemistry Chapter 8 Aldehydes, Ketones and Carboxylic Acids are an excellent source of study material for CBSE Class 12 Chemistry. Here's a clear and exam-focused approach to solving questions:
Be confident with naming –CHO and –CO groups. Differentiate between aldehydes (end groups) and ketones (middle of chain).
Study oxidation of alcohols, ozonolysis of alkenes, and hydration of alkynes. Know reagents like PCC, KMnO₄, CrO₃, etc.
This is the key mechanism: HCN, NaHSO₃, Grignard reagent addition to C=O. Understand the resonance and electrophilicity of carbonyl carbon.
Memorize Tollens’ test (silver mirror), Fehling’s solution (brick-red ppt), and Schiff’s test. These are only for aldehydes, not ketones.
Compare acidity based on substituent effects (–NO₂ increases acidity, –CH₃ decreases it). Learn how resonance stabilizes the carboxylate ion.
Learn decarboxylation (with soda lime), reduction of acids to alcohols, and aldehydes/ketones to respective alcohols using LiAlH₄ or NaBH₄.
Master aldol condensation (for aldehydes and ketones with α-H), Cannizzaro reaction (non α-H aldehydes), and cross-aldol reactions for conversions.
8.1 Nomenclature and Structure of Carbonyl Compounds
8.1.1 Nomenclature
8.1.2 Structure of Carbonyl Compounds
8.2 Preparation of Aldehydes And Ketones
8.2.1 Preparation of Aldehydes And Ketones
8.2.2 Preparation of Aldehydes
8.2.3 Preparation of Ketones
8.3 Physical Properties of Aldehydes and Ketones
8.4 Chemical Reactions of Aldehydes and Ketones
8.5 Uses of Aldehydes and Ketones
8.6 Nomenclature and Structure of Carboxyl Group
8.6.1 Nomenclature
8.6.2 Structure of Carboxyl Group
8.7 Methods of Preparation of Carboxylic Acids
8.8 Physical Properties of Carboxylic Acids
8.9 Chemical Reactions of Carboxylic Acids
8.9.1 Reaction Involving Cleavage of O-H Bond
8.9.2 Reaction Involving Cleavage of C-OH Bond
8.9.3 Reaction Involving -COOH Group
8.9.4 Substitution Reaction in the Hydrocarbon Part
8.10 Uses of Carboxylic Acids
Beyond the NCERT, students should focus on the important concepts and reactions according to the table given below:
Class 12 NCERT Chapter-wise solutions are given below:
Class 12 NCERT subject-wise solutions are given below:
NCERT Solutions for class 12 biology |
NCERT solutions for class 12 maths |
NCERT solutions for class 12 chemistry |
NCERT Solutions for class 12 physics |
Class 12 NCERT subject-wise exemplar solutions are given below:
The NCERT books and syllabus links for class 12 are given below:
Carboxylic acids are more acidic than alcohols but generally less acidic than strong acids such as HCl or H2SO4. The acidity of carboxylic acids is due to the resonance stabilization of the carboxylate anion. Phenols are more acidic than alcohols, but generally less acidic than carboxylic acids.
Due to the presence of both a carbonyl (C=O) and a hydroxyl (-OH) group, carboxylic acids exhibit strong hydrogen bonding. This results in:
Esterification is the reaction of a carboxylic acid with an alcohol in the presence of an acid catalyst, Such as H2SO4.
Changing from the CBSE board to the Odisha CHSE in Class 12 is generally difficult and often not ideal due to differences in syllabi and examination structures. Most boards, including Odisha CHSE , do not recommend switching in the final year of schooling. It is crucial to consult both CBSE and Odisha CHSE authorities for specific policies, but making such a change earlier is advisable to prevent academic complications.
Hello there! Thanks for reaching out to us at Careers360.
Ah, you're looking for CBSE quarterly question papers for mathematics, right? Those can be super helpful for exam prep.
Unfortunately, CBSE doesn't officially release quarterly papers - they mainly put out sample papers and previous years' board exam papers. But don't worry, there are still some good options to help you practice!
Have you checked out the CBSE sample papers on their official website? Those are usually pretty close to the actual exam format. You could also look into previous years' board exam papers - they're great for getting a feel for the types of questions that might come up.
If you're after more practice material, some textbook publishers release their own mock papers which can be useful too.
Let me know if you need any other tips for your math prep. Good luck with your studies!
It's understandable to feel disheartened after facing a compartment exam, especially when you've invested significant effort. However, it's important to remember that setbacks are a part of life, and they can be opportunities for growth.
Possible steps:
Re-evaluate Your Study Strategies:
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Focus on NEET 2025 Preparation:
Seek Support:
Remember: This is a temporary setback. With the right approach and perseverance, you can overcome this challenge and achieve your goals.
I hope this information helps you.
Hi,
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Since you already have a 12th grade qualification with 84%, you meet the qualification criteria and are eligible to apply for the Medhavi Scholarship exam. Make sure to prepare well for the exam to maximize your chances of receiving a higher scholarship.
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hello mahima,
If you have uploaded screenshot of your 12th board result taken from CBSE official website,there won,t be a problem with that.If the screenshot that you have uploaded is clear and legible. It should display your name, roll number, marks obtained, and any other relevant details in a readable forma.ALSO, the screenshot clearly show it is from the official CBSE results portal.
hope this helps.
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