Match the common names given in Column
Question: Match the common names given in Column I with the IUPAC names given in Column II Solution: (i) is d (ii) is e (iii) is a (iv) is b (v) is c...
Read More →Can Gatterman-Koch reaction be considered
Question: Can Gatterman-Koch reaction be considered similar to Friedel Crafts acylation? Discuss. Solution: Both reactions resemble each other. In Friedel Crafts acylation reaction, an aryl group or benzene is treated with an acid chloride in the presence of anhydrous AlCl3 and corresponding aldehyde or ketone is formed. In Gatterman-Koch reaction, benzene is treated with CO and HCl in the presence of AlCl3 and CuCl to yield benzaldehyde....
Read More →Ethylbenzene is generally prepared by acetylation
Question: Ethylbenzene is generally prepared by acetylation of benzene followed by reduction and not by direct alkylation. Think of a possible reason. Solution: This is due to the formation of polysubstituted products. To avoid the formation of polysubstituted products Friedel-crafts alkylation reaction is not used for the preparation of ethylbenzene but one can use Friedel-crafts acylation reaction....
Read More →Why are carboxylic acids more acidic
Question: Why are carboxylic acids more acidic than alcohols or phenols although all of them have a hydrogen atom attached to an oxygen atom (OH)? Solution: Due to the resonance in carboxylic acids, the negative charge is at the more electronegative oxygen whereas, in alcohols or phenols, the negative charge is on a less electronegative atom. Thus, carboxylic acids can release proton easier than alcohols or phenols....
Read More →Why are carboxylic acids more acidic
Question: Why are carboxylic acids more acidic than alcohols or phenols although all of them have a hydrogen atom attached to an oxygen atom (OH)? Solution: Due to the resonance in carboxylic acids, the negative charge is at the more electronegative oxygen whereas, in alcohols or phenols, the negative charge is on a less electronegative atom. Thus, carboxylic acids can release proton easier than alcohols or phenols....
Read More →Identify the compounds A,
Question: Identify the compounds A, B and C in the following reaction. Solution: Compound A = CH3-MgBr Compound B = CH3-COOH Compound C = CH3COOCH3...
Read More →Evaluate the following integrals -
Question: Evaluate the following integrals - $\int(3 x+1) \sqrt{4-3 x-2 x^{2}} d x$ Solution: Let $I=\int(3 x+1) \sqrt{4-3 x-2 x^{2}} d x$ Let us assume $3 x+1=\lambda \frac{d}{d x}\left(4-3 x-2 x^{2}\right)+\mu$ $\Rightarrow 3 x+1=\lambda\left[\frac{d}{d x}(4)-\frac{d}{d x}(3 x)-\frac{d}{d x}\left(2 x^{2}\right)\right]+\mu$ $\Rightarrow 3 x+1=\lambda\left[\frac{d}{d x}(4)-3 \frac{d}{d x}(x)-2 \frac{d}{d x}\left(x^{2}\right)\right]+\mu$ We know $\frac{\mathrm{d}}{\mathrm{dx}}\left(\mathrm{x}^{\m...
Read More →Carboxylic acids contain carbonyl group
Question: Carboxylic acids contain carbonyl group but do not show the nucleophilic addition reaction like aldehydes or ketones. Why? Solution: The oxygen atom in carbonyl compound pull more shared pair of electron towards itself and so, carbon acquires partial positive charge and oxygen acquires partial negative charge in carbonyl compounds. So, the carbon in the carbonyl atom is attacked by a nucleophile. Due to the resonance, carboxylic acids contain carbonyl group do not show the nucleophilic...
Read More →Alkenes and carbonyl compounds both contain a π bond
Question: Alkenes and carbonyl compounds both contain a bond but alkenes show electrophilic addition reactions whereas carbonyl compounds show nucleophilic addition reactions. Explain. Solution: Both the compounds carbon atom is attached to the electronegative atom oxygen. Thus the oxygen pulls more shared pair of electron towards them and a partial positive charge will be acquired by carbon and a partial negative charge by oxygen. So carbonyl atom is attacked by a nucleophile....
Read More →Arrange the following in decreasing order
Question: Arrange the following in decreasing order of their acidic strength. Explain the arrangement. C6H5COOH, FCH2COOH, NO2CH2COOH Solution: NO2CH2COOH FCH2COOH C6H5COOH. NO2CH2COOH is most acidic among the given three compounds. Electron withdrawing groups like -NO2, increases the acidity of carboxylic acids by stabilizing the conjugate base through resonance effects...
Read More →Compound ‘A’ was prepared by oxidation of compound ‘B’
Question: Compound A was prepared by oxidation of compound B with alkaline KMnO4. Compound A on reduction with lithium aluminium hydride gets converted back to compound B. When compound A is heated with compound B in the presence of H2SO4 it produces the fruity smell of compound C to which family the compounds A, B and C belong to? Solution: Compound A belongs to the carboxylic acid. Compound B belongs to alcohol. Compound C belongs to an ester group....
Read More →Arrange the following in decreasing order
Question: Arrange the following in decreasing order of their acidic strength and give the reason for your answer. CH3CH2OH, CH3COOH, ClCH2COOH, FCH2COOH, C6H5CH2COOH Solution: FCH2COOH ClCH2COOH C6H5CH2COOH CH3COOH CH3CH2OH. CH3CH2OH is least acidic among the given compounds. C6H5CH2COOH is more acidic than CH3COOH due to the resonance in C6H5CH2COOH. FCH2COOH and ClCH2COOH are highly acidic due to the I effect of halogen....
Read More →Oxidation of ketones involves carbon-carbon
Question: Oxidation of ketones involves carbon-carbon bond cleavage. Name the products formed on oxidation of 2, 5-dimethylhexan-3-one. Solution: The products formed on oxidation of 2, 5-dimethylhexan-3-one are the mixtures of ketone and carboxylic acids. Ketone is then further oxidized to carboxylic acids. Overall the products formed in this reaction are 2-Methylpropanoic acid, 3-Methylbutanoic acid, ethanoic acid and methanoic acid....
Read More →Mark (√) against the correct answer in the following:
Question: Mark () against the correct answer in the following: The range of $f(x)=a^{x}$, where $a0$ is A. $[-\infty, 0]$ B. $[-\infty, 0)$ C. $[0, \infty)$ D. $(0, \infty)$ Solution: $f(x)=a^{x}$ when $x0$ $0a^{x}1$ When $x \geq 0$ $a^{x}0$ Therefore range of $f(x)=a^{x}=(0, \infty)$...
Read More →Name the electrophile produced in the reaction
Question: Name the electrophile produced in the reaction of benzene with benzoyl chloride in the presence of anhydrous AlCl3. Name the reaction also. Solution: The electrophile produced in the reaction of benzene with benzoyl chloride in the presence of anhydrous AlCl3 is benzoylinium cation. The product formed in this reaction is benzophenone. This reaction is called Friedel Crafts acylation reaction....
Read More →Write IUPAC names of the following structures.
Question: Write IUPAC names of the following structures. Solution: (i) Ethane-1,2-dial. (ii) Benzene-1, 4-dicarbaldehyde. (iii) 3-Bromobenzaldehyde....
Read More →Mark (√) against the correct answer in the following:
Question: Mark () against the correct answer in the following: The range of $f(x)=x+\frac{1}{x}$ is A. $[-2,2]$ B. $[2, \infty)$ C. $(-\infty,-2]$ D. none of these Solution: $\mathrm{f}(\mathrm{x})=\mathrm{x}+\frac{1}{\mathrm{x}}$ For this type Range is $-2 \leq y \geq 2$...
Read More →Give the IUPAC names of the following compounds
Question: Give the IUPAC names of the following compounds Solution: (i) 3-Phenylprop-2-ene-1-al. (ii) Cyclohexanecarbaldehyde (iii) 3-Oxopentan-1-al (iv) IUPAC name: But-2-enal...
Read More →Mark (√) against the correct answer in the following:
Question: Mark () against the correct answer in the following: Let $f(x)=\frac{x^{2}}{\left(1+x^{2}\right)} .$ Then, range $(f)=?$ A. $[1, \infty)$ B. $[0,1)$ C. $[-1,1]$ D. $(0,1]$ Solution: $\mathrm{f}(\mathrm{x})=\frac{\mathrm{x}^{2}}{1+\mathrm{x}^{2}}$ $\Rightarrow \mathrm{y}=\frac{\mathrm{x}^{2}}{1+\mathrm{x}^{2}}$ $\Rightarrow \mathrm{y}+\mathrm{yx}^{2}=\mathrm{x}^{2}$ $\Rightarrow \mathrm{y}=\mathrm{x}^{2}(1-\mathrm{y})$ $\Rightarrow x=\sqrt{\frac{y}{1-y}}$ $\frac{y}{1-y} \geq 0$ $\Righta...
Read More →Write a test to differentiate between
Question: Write a test to differentiate between pentan-2-one and pentan-3-one. Solution: One can differentiate between pentan-2-one and pentan-3-one by iodoform test. Pentan-2-one have a CO-CH3 group and therefore forms a yellow precipitate of Iodoform. Pentan-2-one gives a positive iodoform test, whereas, and pentan-3-one does not give a positive iodoform test because they dont have a CO-CH3 group....
Read More →Evaluate the following integrals -
Question: Evaluate the following integrals - $\int(x+3) \sqrt{3-4 x-x^{2}} d x$ Solution: Let $I=\int(x+3) \sqrt{3-4 x-x^{2}} d x$ Let us assume $x+3=\lambda \frac{d}{d x}\left(3-4 x-x^{2}\right)+\mu$ $\Rightarrow \mathrm{x}+3=\lambda\left[\frac{\mathrm{d}}{\mathrm{dx}}(3)-\frac{\mathrm{d}}{\mathrm{dx}}(4 \mathrm{x})-\frac{\mathrm{d}}{\mathrm{dx}}\left(\mathrm{x}^{2}\right)\right]+\mu$ $\Rightarrow \mathrm{x}+3=\lambda\left[\frac{\mathrm{d}}{\mathrm{dx}}(3)-4 \frac{\mathrm{d}}{\mathrm{dx}}(\math...
Read More →Why is there a large difference in
Question: Why is there a large difference in the boiling points of butanal and butane-1-ol? Solution: Butanal has no intermolecular hydrogen bonding but butan-1-ol has intermolecular hydrogen bonding. This bonding in butan-1-ol makes it more stable at a higher temperature than butanal....
Read More →Which of the following is the correct representation
Question: Which of the following is the correct representation for intermediate of nucleophilic addition reaction to the given carbonyl compound (A) : Solution: Option (A) and (B) are the answers....
Read More →Mark (√) against the correct answer in the following:
Question: Mark () against the correct answer in the following: Let $f(x)=\frac{1}{\left(1-x^{2}\right)} \cdot$ Then, range $(f)=?$ A. $(-\infty, 1]$ B. $[1, \infty)$ C. $[-1,1]$ D. none of these Solution: $f(x)=\frac{1}{1-x^{2}}$ $\Rightarrow \mathrm{y}=\frac{1}{1-\mathrm{x}^{2}}$ $\Rightarrow \mathrm{y}-\mathrm{yx}^{2}=1$ $\Rightarrow \mathrm{y}-1=\mathrm{yx}^{2}$ $\Rightarrow x=\sqrt{\frac{y-1}{y}}$ $\Rightarrow \frac{y-1}{y} \geq 0$ $\Rightarrow \mathrm{y} \geq 1$ $\therefore$ range $(f)=[1, ...
Read More →Benzophenone can be obtained
Question: Benzophenone can be obtained by ____________. (i) Benzoyl chloride + Benzene + AlCl3 (ii) Benzoyl chloride + Diphenyl cadmium (iii) Benzoyl chloride + Phenyl magnesium chloride (iv) Benzene + Carbon monoxide + ZnCl2 Solution: Option (i)Benzoyl chloride + Benzene + AlCl3and (ii)Benzoyl chloride + Diphenyl cadmium are the answers...
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