Sucrose (cane sugar) is a disaccharide.
Question: Sucrose (cane sugar) is a disaccharide. One molecule of sucrose on hydrolysis gives _________. (i) 2 molecules of glucose (ii) 2 molecules of glucose + 1 molecule of fructose (iii) 1 molecule of glucose + 1 molecule of fructose (iv) 2 molecules of fructose Solution: Option (iii)1 molecule of glucose + 1 molecule of fructoseis the answer....
Read More →Evaluate the following integral:
Question: Evaluate the following integral: $\int \frac{5 x}{(x+1)\left(x^{2}-4\right)} d x$ Solution: $\frac{5 x}{(x+1)\left(x^{2}-4\right)}=\frac{5 x}{(x+1)(x-2)(x+2)}$ The denominator is factorized, so let separate the fraction through partial fraction, hence let $\frac{5 x}{(x+1)(x-2)(x+2)}=\frac{A}{x+1}+\frac{B}{x-2}+\frac{C}{x+2} \ldots \ldots$ (i) $\Rightarrow \frac{5 x}{(x+1)(x-2)(x+2)}$ $=\frac{\mathrm{A}(\mathrm{x}-2)(\mathrm{x}+2)+\mathrm{B}(\mathrm{x}+1)(\mathrm{x}+2)+\mathrm{C}(\math...
Read More →Which of the following polymer is stored
Question: Which of the following polymer is stored in the liver of animals? (i) Amylose (ii) Cellulose (iii) Amylopectin (iv) Glycogen Solution: Option (iv) Glycogen is the answer....
Read More →Let a * b = 1 cm (a, b) for all values ofa, b ∈ N.
Question: Let a * b = 1 cm (a, b) for all values ofa, b N. (i) Find $(12 * 16)$. (ii) Show that * is commutative on $\mathrm{N}$. (iii) Find the identity element in $\mathrm{N}$. (iv) Find all invertible elements in N. Solution: To find: (i) LCM of 12 and 16 Prime factorizing 12 and 16 we get. $20=2^{2} \times 3$ $16=2^{4}$ $\Rightarrow \mathrm{LCM}$ of 20 and $16=2^{4} \times 3=48$ (ii) To find LCM highest power of each prime factor has been taken from both the numbers and multiplied. So it is ...
Read More →Glycogen is a branched-chain polymer of α-D-glucose
Question: Glycogen is a branched-chain polymer of -D-glucose units in which chain is formed by C1C4 glycosidic linkage whereas branching occurs by the formation of C1-C6 glycosidic linkage. Structure of glycogen is similar to __________. (i) Amylose (ii) Amylopectin (iii) Cellulose (iv) Glucose Solution: Option (ii)Amylopectin is the answer....
Read More →Let * be a binary operation on N, defined
Question: Let $*$ be a binary operation on $N$, defined by $a * b=a^{b}$ for all $a . b \in N$. Show that * is neither commutative nor associative. Solution: To prove: $*$ is neither commutative nor associative Let us assume that $*$ is commutative $\Rightarrow a^{b}=b^{a}$ for $a l l a, b \in N$ This is valid only for $\mathrm{a}=\mathrm{b}$ For example take $a=1, b=2$ $1^{2}=1$ and $2^{1}=2$ So * is not commutative Let us assume that * is associative $\Rightarrow\left(a^{b}\right)^{c}=a^{b^{c}...
Read More →Evaluate the following integral:
Question: Evaluate the following integral: $\int \frac{\mathrm{x}^{2}}{(\mathrm{x}-1)(\mathrm{x}-2)(\mathrm{x}-3)} \mathrm{dx}$ Solution: Denominator is already factorized, so let $\frac{\mathrm{x}^{2}}{(\mathrm{x}-1)(\mathrm{x}-2)(\mathrm{x}-3)}=\frac{\mathrm{A}}{\mathrm{x}-1}+\frac{\mathrm{B}}{\mathrm{x}-2}+\frac{\mathrm{C}}{\mathrm{x}-3} \ldots \ldots(\mathrm{i})$ $\Rightarrow \frac{x^{2}}{(x-1)(x-2)(x-3)}$ $=\frac{A(x-2)(x-3)+B(x-1)(x-3)+C(x-1)(x-2)}{(x-1)(x-2)(x-3)}$ $\Rightarrow \mathrm{x}...
Read More →Arrange the following compounds in increasing
Question: Arrange the following compounds in increasing order of dipole moment. CH3CH2CH3, CH3CH2NH2, CH3CH2OH Solution: CH3CH2CH3 CH3CH2NH2 CH3CH2OH The dipole moment of CH3CH2OH is greater than that of CH3CH2NH2. CH3CH2CH3 has the least dipole moment among the three given compounds because it is almost a non-polar molecule....
Read More →Predict the product of the reaction of aniline
Question: Predict the product of the reaction of aniline with bromine in a non-polar solvent such as CS2. Solution: The products formed in the reaction of aniline with bromine in a non-polar solvent such as CS2 are 4-Bromoaniline and 2-Bromoaniline where 4-Bromoaniline is the major product....
Read More →Show that * on Z + defined
Question: Show that $*$ on $Z+$ defined by $a * b=|a-b|$ is not a binary operation. Solution: To prove: * is not a binary operation Given: a and b are defined on positive integer set And $a * b=|a-b|$ $\Rightarrow a * b=(a-b)$, when $ab$ $=b-a$ when $ba$ $=0$ when $a=b$ But 0 is neither positive nor negative. So 0 does not belong to $Z^{+}$. So $a * b=|a-b|$ does not belong to $Z+$ for all values of $a$ and $b$ So $*$ is not a binary operation. Hence proved...
Read More →Under what reaction conditions (acidic/basic),
Question: Under what reaction conditions (acidic/basic), the coupling reaction of aryldiazonium chloride with aniline is carried out? Solution: This reaction is carried out in a mild basic medium. This is an electrophilic substitution reaction. Aryldiazonium chloride reacts with aniline to form a yellow dye of p-Aminoazobenzene....
Read More →What is the role of pyridine in the acylation
Question: What is the role of pyridine in the acylation reaction of amines? Solution: The activating effect of NH2 group can be controlled by protecting the -NH2 group by acetylation with acetic anhydride in presence of pyridine and then carrying out the desired substitution followed by hydrolysis of the substituted amide to the substituted amine. Pyridine is a base that is used to get rid of HCl as a side product from the reaction....
Read More →Explain why MeNH2 is a stronger
Question: Explain why MeNH2 is a stronger base than MeOH? Solution: MeNH2 is a stronger base than MeOH because of the lower electronegativity and the presence of the lone pair of electrons on the nitrogen atom in MeNH2....
Read More →If * be the binary operation on the set Z of all integers defined
Question: If $*$ be the binary operation on the set $Z$ of all integers defined by $a * b\left(a+3 b^{2}\right)$, find $2 * 4$ Solution: To find: $2 * 4$ Given: $a * b=a+3 b^{2}$ $\Rightarrow 2 * 4=\left(2+3 \times 4^{2}\right)=2+48=50$...
Read More →Why does the acetylation of —NH2
Question: Why does the acetylation of NH2 group of aniline reduce its activating effect? Solution: The acetylation of NH2 group of aniline reduces its activating effect because the lone pair of electrons on the nitrogen of acetanilide interacts with oxygen atom due to resonance....
Read More →Why is benzene diazonium chloride not stored
Question: Why is benzene diazonium chloride not stored and is used immediately after its preparation? Solution: Benzene diazonium chloride is highly soluble in water at high temperature and is itself very stable at low temperature. It should be used immediately after its preparation as it is unstable....
Read More →Let * be a binary operation on N given
Question: Let * be a binary operation on N given by a *b = 1 cm of a and b. Find the value of20 * 16. Is * (i) commutative, (ii) associative? Solution: To find: LCM of 20 and 16 Prime factorizing 20 and 16 we get. $20=2^{2} \times 5$ $16=2^{4}$ $\Rightarrow$ LCM of 20 and $16=2^{4} \times 5=80$ (i) To find LCM highest power of each prime factor has been taken from both the numbers and multiplied. So it is irrelevant in which order the number are taken as their prime factors will remain the same....
Read More →What is Hinsberg reagent?
Question: What is Hinsberg reagent? Solution: Benzenesulphonyl chloride or, C6H5SOCl is commonly known as Hinsbergs reagent. Hinsbergs reagent is be used to distinguish primary, secondary and tertiary amines....
Read More →Evaluate the following integral:
Question: Evaluate the following integral: $\int \frac{x^{2}+1}{x^{2}-1} d x$ Solution: First we simplify numerator, we get $\frac{x^{2}+1}{x^{2}-1}$ $=\frac{x^{2}-1+2}{x^{2}-1}$ $=\frac{x^{2}-1}{x^{2}-1}+\frac{2}{x^{2}-1}$ $=1+\frac{2}{(x-1)(x+1)}$ Now the denominator is factorized, so let separate the fraction through partial fraction, hence let $\frac{2}{(x+1)(x-1)}=\frac{A}{x+1}+\frac{B}{x-1} \ldots \ldots$ (i) $\Rightarrow \frac{2}{(x+2)(x-1)}=\frac{A(x-1)+B(x+1)}{(x+2)(x-1)}$ $\Rightarrow ...
Read More →What is the best reagent to convert
Question: What is the best reagent to convert nitrile to primary amine? Solution: The best reagents for the conversion of nitrile to primary amine are LiAlH4 and Sodium/Alcohol. By reduction, the nitriles can be converted into a corresponding primary amine....
Read More →What is the product when C6H5CH2NH2
Question: What is the product when C6H5CH2NH2 reacts with HNO2? Solution: C6H5CH2NH2 reacts with HNO2 to form unstable diazonium salt, which in turn gives alcohol. C6H5CH2NH2 + HNO2 C6H5CH2OH + N2 + H2O...
Read More →Why is NH2 group of aniline acetylated
Question: Why is NH2 group of aniline acetylated before carrying out nitration? Solution: To control the nitration reaction and tarry oxidation products and nitro derivatives products formation, the NH2 group of aniline is acetylated before carrying out nitration. Here, the major product is p-nitroaniline....
Read More →What is the role of HNO3 in the nitrating
Question: What is the role of HNO3 in the nitrating mixture used for nitration of benzene? Solution: Nitrating mixture is the mixture of 1:1 solution of HNO3 and H2SO4 and is used for the nitration of organic compounds. It acts as a base and provides electrophile in the nitration process of benzene....
Read More →Which of the following reactions belong
Question: Which of the following reactions belong to electrophilic aromatic substitution? (i) Bromination of acetanilide (ii) Coupling reaction of aryldiazonium salts (iii) Diazotisation of aniline (iv) Acylation of aniline Solution: Option (i) and (ii) are the answers....
Read More →Let be a binary operation on the set Q of all rational numbers given as
Question: Let be a binary operation on the set $\mathrm{Q}$ of all rational numbers given as $\mathrm{a} * \mathrm{~b}=(2 \mathrm{a}-\mathrm{b})^{2}$ for all $\mathrm{a}, \mathrm{b} \in$ Q. Find $3 * 5$ and $5 * 3$. Is $3 * 5=5 * 3$ ? Solution: To find: $3 * 5$ and $5 * 3$ Given: $a * b=(2 a-b)^{2}$ $\Rightarrow 3 * 5=(6-5)^{2}=1$ Now $5^{*} 3=(10-3)^{2}=49$ $\Rightarrow 3 * 5$ is not equal to $5 * 3$...
Read More →