Recent questions tagged sec-c

If $A = \begin{bmatrix} 1 & \tan x \\ -\tan x & 1 \end{bmatrix} $ , Evaluate $A^TA^{-1}$

asked Dec 1, 2016 by priyanka.c

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Find the value of $\tan^{-1} (\frac{x}{y}) - \tan^{-1}(\frac{x-y}{x+y})$

asked Nov 30, 2016 by priyanka.c

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Define a binary operation $\ast$ on the set {0, 1, 2, 3, 4, 5} as \[a*b=\left \{ \begin{array} {1 1} a+b, & \quad \text{ if a+b<6} \\ a+b-6, & \quad { if a+b \geq 6} \end{array} \right.\] show that the zero is the identity for this operation and each element $a \neq 0$ of the set is invertible with $6-a$ being the inverse of $a$.

asked Nov 30, 2016 by priyanka.c

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What are cannabinoids? From which plant are cannabinoids obtained? Which part of the body is affected by consuming these substances?

asked Nov 30, 2016 by meena.p

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State Hardy-Weinberg principle. When there is a disturbance in the Hardy-Weinberg equilibrium, what would it result in? According to this principle, what is the sum total of all allelic frequencies?

asked Nov 30, 2016 by meena.p

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Give six points of difference between DNA and RNA in their structural chemistry and their function.

asked Nov 30, 2016 by meena.p

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A woman with blood group “O” marries a man with “AB” blood group a)Work out all the possible phenotypes and genotypes of progeny. b)Discuss the kind of dominance in parents and progeny in their case.

asked Nov 30, 2016 by meena.p

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Differentiate between tubectomy and vasectomy.Mention the techniques that are employed in the following cases: a)Transfer of ovum collected from a donor into the fallopian tube of another female who cannot produce ova but can provide suitable environment for fertilization and development. b) Embryo is formed in the laboratory in which sperm is directly injected into the ovum. c)Semen collected either from husband or healthy donor is artificially introduced either into the ****** or uterus.

asked Nov 30, 2016 by meena.p

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Which of the following polymers soften on heating and harden on cooling? What are the polymers with this property collectively called? What are the structural similarities between such polymers?

asked Nov 28, 2016 by meena.p

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Write about the following on protein synthesis . (i) Name the location where protein synthesis occurs . (ii) How do 64 codons code code for only 20 amino acids? (iii) Which of the two bases of the condon are more important for coding ?

asked Nov 28, 2016 by meena.p

1 answer

State reasons for the following : (i) $pKb$ value for aniline is more than that for methylamine. (ii) Ethylamine is soluble in water whereas aniline is not soluble in water. (iii) Primary amines have higher boiling points than tertiary amines.

asked Nov 28, 2016 by meena.p

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Draw the structure of : (i) 3- methyl butanal (ii) 4- chloropentan-2-one (iii) 3-oxopentanal

asked Nov 25, 2016 by meena.p

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Give names of the reagents to bring about the following transformations: (i) Hexan-1-ol to hexanal (ii) Cyclohexanol to cyclohexanone (iii) P-Fluorotoluene to p-Fluorobenzaldehyde (iv) Ethanenitrile to ethanal (v) Allyl alcohol to propenal

asked Nov 25, 2016 by meena.p

1 answer

How would you account for the following (i) Aldehydes are more reactive than ketones towards nucleophiles (ii) The boiling points of aldehydes and ketones are lower than of the corresponding acids (iii) The aldehydes and ketones undergo a number of addition reactions.

asked Nov 25, 2016 by meena.p

1 answer

$Fe^{3+} \longrightarrow (A) \quad \longrightarrow \quad (B)$ What are (A) and (B) ? Give IUPAC name of (A) . Find the Spin only magnetic moment of $(B)$

asked Nov 25, 2016 by meena.p

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(i) Are all the five bonds in $PCl_5$ molecules equivalent ? justify your answer. (ii) What happens when $PCl_5$ is heated ?

asked Nov 25, 2016 by meena.p

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(a) Why refractory metals are used in the construction of furnaces ? (b) What is pyrometallurgy ?

asked Nov 25, 2016 by meena.p

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Explain how the phenomenon of absorption finds application in each of the following process : (i) Production of vaccum (ii) Heterogeneous catalysis

asked Nov 25, 2016 by meena.p

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Iron and nickel are used to make electro chemical cell by using a salt bridge to join a half cell containing $1\;M\;Fe^{2+}(aq)$ in which a strip of irons has been immersed to a second half cell which contain $1\;M\;Ni^{2+}(aq)$ in which a strip of Ni has been immersed ? A voltmeter is connected between the two metal strips : $E^{0} _{Fe^{2+}/Fe} =-0.44 V; \qquad E^{0} _{Ni^{2+}/Ni} =-0.25 V $ a) Write the name of the cathode and anode . b) Write the half reaction involved ? c) What would be the effect on the voltmeter reading if $Fe^{2+}$ concentration were increased ?

asked Nov 24, 2016 by meena.p

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When fruits and vegetables that have dried are placed in water , they slowly swell and return to the original form . Explain why ? Would a temperature increase accelerate the process explain .

asked Nov 24, 2016 by meena.p

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Explain elastomeric polymers and fibres

asked Nov 22, 2016 by meena.p

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Glucose or sucrose are soluble in water but cyclohexane or benzene are insoluble in water. Explain.

asked Nov 22, 2016 by meena.p

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Arrange the following (i) In decreasing order of basic strength in gas phase : $C_2H_5NH_2, (C_2H_5)_2NH, (C_2H_5)_3 N$ and $NH_3$ (ii) In increasing order of boiling point : $C_2H_5OH, (CH_3)_2NH,C_2H_5NH_2$

asked Nov 22, 2016 by meena.p

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An organic compound $(A)\; \{C_8H_{16}O_2\}$ was hydrolysed with dilute sulphuric acid to give a carboxylic acid $(B)$ and an alcohol $(C)$. Oxidation of $(C)$ with chromic acid produced $(B)$.$(C)$ on dehydration gives but‐1‐ene .Identity $A,B,C$

asked Nov 22, 2016 by meena.p

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(i) Why pH of reaction should be carefully controlled while preparing ammonia derivatives of carbonyl compound? (ii) Why formic acid is stronger acid than acetic acid

asked Nov 22, 2016 by meena.p

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How would you account for the following $NF_3$ is an exothermic compounds but $NCl_3$ is not.

asked Nov 22, 2016 by meena.p

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Why is the silver plating of copper $k[Ag(CN)_2]$is used instead of $AgNO_3$ ?

asked Nov 22, 2016 by meena.p

1 answer

Complete the following chemical equations : (i) $P_4+SO_2 Cl_2 \to \\ (ii)Fe^{3+}+SO_2+H_2O \to \\ (iii) X_eF_6+H_2 O \to $

asked Nov 22, 2016 by meena.p

1 answer

Describe how the following changes are brought about : (i) Pig irons into steel (ii) Zinc oxide into metallic zinc

asked Nov 22, 2016 by meena.p

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$SnO_2$ forms a positively charged colloidal Sol in the basic medium why ?

asked Nov 22, 2016 by meena.p

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The following curve is obtained when molar conductivity $(\lambda_m)$ is plotted against the square root of concentration for 2 electrolytes A and B (a) What can you say about the nature of the two electrolyte $A\; \&\;B$ (b) How do you account for the increase in molar conductivity $\lambda_m$ for the electrolyte A and B on dilution

asked Nov 21, 2016 by meena.p

1 answer

$18\;g$ of glucose , $C_6H_{12}$ is dissolved in $1\;kg$ of water in a sauce pan. At what temperature will water boil at $1.013$ bar ? $K_b$ for water is $0.52\;k\;kg\;mol^{-1}$

asked Nov 21, 2016 by meena.p

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Explain : (i) The molecules $NH_3$ and $NF_3$ have dipole moments which are of opposite direction . (ii) Sulphur in vapour state exhibits paramagnetism

asked Nov 17, 2016 by meena.p

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Explain the following terms giving one example of each type (i) Antacids (ii) Disinfectants

asked Nov 17, 2016 by meena.p

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15.0 g of unknown molecular material was dissolved in 450 g of water. The resulting solution was found freezes at $−0.34^{\large\circ}$C. What is the molar mass of this material? ($K_f$ for water = $1.86 \;K\; kg \;mol^{−1}$)

asked Nov 16, 2016 by meena.p

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What is observed when : (i) A beam of light is passed through a colloidal solution ? (ii) Electric current is passed through a colloidal solution ?

asked Nov 16, 2016 by meena.p

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Give reasons— (a) Interhalogen compounds are more reactive than halogens (b) $PCl_5$ is known but $NCl_5$ is not known. (c) Amongst all noble gases, only xenon is known to form compounds with oxygen and fluorine.

asked Nov 16, 2016 by meena.p

1 answer

An aromatic compound $(A)$ on treatment with ammonia followed by heating forms compound $(B)$, which on heating with $Br_2$ and $KOH$ forms a compound $(C)$ having molecular formula $C_6H_7N$. Give the structures of $A, B$ and $C$ and write the reactions involved.

asked Nov 16, 2016 by meena.p

1 answer

Give one example for each of the following :(a) An artificial sweetener whose use is limited to cold drinks.(b) A non-ionic detergent.(c) A pain reliever used for relief from severe pains like post-operative pain or pain due to terminal cancer.

asked Nov 16, 2016 by meena.p

1 answer

(a) Give an example of a synthetic rubber and mention its main advantage. (b) Write the structures of the monomers of Dacron. (c) Arrange the following polymers in the increasing order of tensile strength. Nylon-6, Buna-S, Polythene.

asked Nov 16, 2016 by meena.p

1 answer

a)Give reasons for the following : (i) Glucose does not give 2,4-DNP test and Schiff’s test (ii) Amino acids have high melting points and are soluble in water. (b) What is meant by the secondary structure of proteins?

asked Nov 16, 2016 by meena.p

1 answer

In a hydrolysis reaction, $5\;g$ ethyl acetate is hydrolysed in presence of dilute HCl in $300\; minutes$. If the reaction is of first order and the initial concentration of ethyl acetate is $22\;g/L$, calculate the rate constant of the reaction.

asked Nov 16, 2016 by meena.p

1 answer

Draw the structure of the following $a)H_2S_2O_8 \\ b)X_eO_3 \\ c) HOClO_2 $

asked Nov 15, 2016 by meena.p

1 answer

a) What is the role of depressent in froth flotation process ? b) Out of C and CO, which is a better reducing agent for FeO? (i) In the lower part of blast furnace (Higher temperature ) (ii) In the upper part of blast furnace (lower temperature )

asked Nov 15, 2016 by meena.p

1 answer

Gold (atomic mass $=197\;v$ atomic radius $=0.144\;nm$) crystallizers in a face centered unit cell . Determined the density of gold $[N_A=6.022 \times 10^{23}mol^{-1}]$

asked Nov 14, 2016 by meena.p

1 answer

Answer the following : (i) Haloalkanes easily dissolve in organic solvent why ? (ii) What is known as a racemic mixture ? Give an example

asked Nov 14, 2016 by meena.p

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Between Sodium hydrogen carbonate and magnesium hydroxide which is a better antacid and why ?

asked Nov 14, 2016 by meena.p

1 answer

Write about the following on protein synthesis. (a) Name the location where protein synthesis occurs . (b) How do 64 codons code for only 20 amino acids (c) Which of the two bases of the codon are more important for coding ?

asked Nov 14, 2016 by meena.p

1 answer

Write the following conversions : $(i) nitrobenzene \to acetanilide \\ (ii) acetanilide \to p-nitroanilne$

asked Nov 11, 2016 by meena.p

1 answer

Account for the following : Sodium bisulphites is used for the purification of aldehydes and ketones .

asked Nov 11, 2016 by meena.p

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