Recent questions tagged ch-11

An alcohol A $(C_4H_{10}O)$ on oxidation with acidified potassium dichromate gives carboxylic acid B $(C_4H_8O_2)$. Compound A when dehydrated with conc. $H_2SO_4$ at $443 \;K$ gives compound C. Treatment of C with aqueous $H_2SO_4$ gives compound D $(C_4H_{10}O)$ which is an isomer of A. Compound D is resistant to oxidation but compound A can be easily oxidised. Identify A, B, C and D and write their structures

asked Dec 29, 2016 by meena.p

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An organic compound A having molecular formula $C_6H_6O$ gives a characteristic colour with aqueous $FeCl_3$ . When A is treated with $NaOH$ and $CO_2$ at $400\;K$ under pressure, compound B is obtained. Compound B on acidification gives compound C which reacts with acetyl chloride to form D which is a popular pain killer. Deduce the structure of A, B, C and D. What is the common name of Drug D?

asked Dec 29, 2016 by meena.p

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(a)Which of the following is an appropriate set of reactants for the preparation of 1-methoxy-4-nitrobenzene and why?

asked Nov 29, 2016 by meena.p

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Explain the following observations: (i) The boiling point of ethanol is higher than that of methoxy methane. (ii) Phenol is more acidic than ethanol (iii) O-and -P - nitrophenols are more acidic than phenol . (iv) Phenol is an acid but does not react with sodium bicarbonate solution .

asked Nov 29, 2016 by meena.p

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Ethyl alcohol to which another liquid has been added to make it unfit for use as beverage is called denatured alcohol. Ethyl alcohol denatured by adding methyl alcohol, is highly poisonous. Answer the following questions: (i) Mention another way by which alcohol is denatured. (ii) Explain why methanol is highly toxic to human beings? (iii) How is methanol prepared on large-scale? Give its two important uses.

asked Nov 28, 2016 by meena.p

1 answer

An aromatic compound 'A' on treatment with $CHCl_3/KOH$ gives two compounds 'B' and 'C'. Both B and C give the same product 'D' when distilled with zinc dust. oxidation of D gives E having molecular formula $C_7H_6O_2$. The sodium salt of E on heating with sodalime gives F which may also be obtained by distilling A with Zinc dust . Identify A to F

asked Nov 23, 2016 by meena.p

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Write two important uses of formalin .

asked Nov 14, 2016 by meena.p

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(a) Give the equation of reaction for the preparation of phenol from cumene. (b) Write the chemical reaction for the preparation of phenol from chloro benzene

asked Nov 11, 2016 by meena.p

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a)i)The resistance of a conductivity cell containing $0.001\;M\; KCl$ solution at $298\;K$ is $1500 \Omega$. What is the cell constant, if the conductivity of $0.001\;M\; KCl$ solution at $298\;K$ is $0.146 \times 10^{-3}\;S\;cm^{-1}$? ii)Explain with one example each the terms weak and strong electolytes iii)The standard reduction potential values of three metallic cations $X,Y, Z$ are $+0.52, − 3.03, − 1.18 V$ respectively. What will be the order of reducing power of the corresponding metals? b) Distinguish between rate expression and rate constant of a reaction

asked Nov 10, 2016 by meena.p

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(a) Write a suitable chemical equation to complete each of the following transformations: (i) Butan-1-ol to butanoic acid . ( ii) 4 -Methylacetophenone to benzene -1,4-dicarboxylic acid (b) Suggest a reagent for conservation of ethanol to ethanoic acid

asked Nov 9, 2016 by meena.p

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Name the alkyl halide and sodium alkaloid used to synthesize tert - butyl ether

asked Nov 8, 2016 by meena.p

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Show how will you synthesize : (i) 1- phenylethanol from a suitable alkene (ii) cyclohexyl methanol using an alkyl halide by an $SN^2$ reaction . (iii) Pentan-1-ol using a suitable alkyl halide ?

asked Nov 7, 2016 by meena.p

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How do you account for the miscibility of ethoxyethane with water.

asked Nov 4, 2016 by meena.p

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(a) Illustrate the following reactions giving a suitable example for each : (i) Cross aldol condensation (ii) Decarboxylation (b) Give Simple tests to distinguish between the following pairs of compounds : (i) Pentan -2-one and pentan -3-one (ii) Benzaldehyde and Acetophenone (iii) Phenol and Benzoic acid .

asked Nov 2, 2016 by meena.p

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Lower alcohol are soluable in water higher alcohols are not why ?

asked Nov 1, 2016 by meena.p

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Explain why phenols do not undergo substitution of the -OH group like alcohols ?

asked Oct 31, 2016 by meena.p

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Although chlorine is an electron with drawing group , yet it is ortho- , Para - directing in electrophilic aromatic substitution reaction . Explain why it is so ?

asked Oct 26, 2016 by meena.p

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Suggest a reagent for conservation of ethanol to ethanoic acid

asked Oct 25, 2016 by meena.p

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(a) Give names of the reagents to bring about the following transformations : (i) Ethanoic acid to ethanol (ii) Propan -1-ol to propanal (iii) Pent -3-en-2-ol pent-3-en-2-one (iv) Sodium benzoate to benzene (b) Arrange in the following in increasing order of : (i) Methanal , Propanal, Butanone, ethanal,Propanone(Nucleophilic addition reaction ) (ii) Formaldehyde , Acetone , Acetaldehyde (reactivity towards HCN) (iii) Acetophenone, p- tolualdehyde, p-nitrobenzaldehyde, Benzaldehyde(nucleophilic addition reaction ).

asked Oct 24, 2016 by meena.p

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How will you prepare benzyl alcohol from benzaldehyde with out using a reducing agent ?

asked Oct 21, 2016 by meena.p

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Arrange the following in order of decreasing acid strength $CH_3OH, H_2O ,C_6H_5OH$

asked Oct 21, 2016 by meena.p

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Light of frequency $7.21 \times 10^{14} Hz$ is incident on a metal surface . Electron with a maximum speed of $6.0 \times 10^5\;ms^{-1}$ are ejected from the surface. What is the threshold frequency for photo emission of electron ? $ h =6.63 \times 10^{-34}Js, m_e=9.1 \times 10^{-31} \;kg$

asked Jun 22, 2016 by meena.p

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The work function for a certain metal is $4.2\;ev$ will this metal give photo electric emission for incident radiation of wave length $330 nm? $

asked Jun 22, 2016 by meena.p

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The threshold frequency of a certain metal is $3.3 \times 10^{14}\;Hz$ . If light of frequency $8.2 \times 10^{14}\;Hz$ is incident on the metal, Predict the cut off voltage for photo electric emission . Given Planck's Constant , $h= 6.62 \times 10^{-34} \;Js$

asked Jun 22, 2016 by meena.p

1 answer

A 100 w sodium lamp radiates energy uniformly in all directions. The lamp is located at the center of a large sphere that absorbs all the sodium light which is incident on it. The wavelength of the sodium light is $589\;nm$ At what rate are the photons delivered to the sphere ?

asked Jun 22, 2016 by meena.p

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A 100 w sodium lamp radiates energy uniformly in all directions. The lamp is located at the center of a large sphere that absorbs all the sodium light which is incident on it. The wavelength of the sodium light is $589\;nm$ what is the energy associated per photon with the sodium light ?

asked Jun 22, 2016 by meena.p

1 answer

Is an experiment on photo effect, the slope of the cut off voltage versus frequency of incident light is found to be $4.12 \times 10^{-15} Vs $ given $e= 1.6 \times 10^{-19}\;c$ estimate the value of planes constant

asked Jun 21, 2016 by meena.p

1 answer

The energy flux of sun light reaching the surface of the earth is $1.388 \times 10^3 w/m^2$. How many photons (nearly) per sq.m are incident on the earth per sec ? Assume that the photons in the sunlight have an average wave length of $550 \;nm$

asked Jun 21, 2016 by meena.p

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Monochromatic light of wave length $632.8\;nm$ is produced by a helium - neon laser. The power emitted is $9.42\;mw$. How fast does a hydrogen atom have to travel in order to have the same momentum as that of the photon .

asked Jun 21, 2016 by meena.p

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Monochromatic light of wave length $632.8\;nm$ is produced by a helium - neon laser. The power emitted is $9.42\;mw$. How many photons per energy, on the average, arrive at a target irradiated by this beam ? (Assume the beam to have uniform cross - section which is less than the target area )

asked Jun 21, 2016 by meena.p

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Monochromatic light of wave length $632.8\;nm$ is produced by a helium - neon laser. The power emitted is $9.42\;mw$. Find the energy and momentum of each photon in the light beam

asked Jun 21, 2016 by meena.p

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The photoelectric cut off voltage in a certain experiment is $1.5 \;v$ What is the maximum kinetic energy of photo electron emitted ?

asked Jun 21, 2016 by meena.p

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The work function of caesium metal is $2.14$ ev when light of frequency $6 \times 10^4 \;Hz$ is incident on the metal surface , photo emission of electron occur. what is the a) maximum speed of the emitted photo electrons

asked Jun 21, 2016 by meena.p

1 answer

The work function of caesium metal is $2.14$ ev when light of frequency $6 \times 10^4 \;Hz$ is incident on the metal surface , photo emission of electron occur. what is the stopping potential

asked Jun 21, 2016 by meena.p

1 answer

The work function of caesium metal is $2.14$ ev when light of frequency $6 \times 10^4 \;Hz$ is incident on the metal surface , photo emission of electron occur. what is the a) maximum kinetic energy of emitted electrons

asked Jun 21, 2016 by meena.p

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Find the minimum wave length of x - rays produced by $30\; kv$ electron . given $h= 6.63 \times 10^{-34}\;Js$

asked Jun 21, 2016 by meena.p

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Find the maximum frequency of x- rays produced by $30\; kv$ electrons. Given, $h= 6.63 \times 10^{-34}\;Js$

asked Jun 21, 2016 by meena.p

1 answer

In the following sequence of reaction $CH_3CH_2OH \quad \underrightarrow {P+I_2} \quad A \quad \underrightarrow {Mg} \quad B \quad \underrightarrow {HCHO} \quad C \quad \underrightarrow {H_2O} D$ the compound D is :

asked Dec 8, 2015 by meena.p

1 answer

In the reaction sequence : $CaC_2 \quad \underrightarrow {H_2O} \quad A \quad \underrightarrow {dil.H_2SO_4} \quad B \quad \underrightarrow {H_2/Ni}\quad C$, the term C is

asked Dec 8, 2015 by meena.p

1 answer

In the following sequence of reactions $CH_3-Br \quad$$ \underrightarrow {KCN} A\quad \underrightarrow{H_3 O} \quad B \underrightarrow{LiAlH_4} \quad C$

asked Dec 8, 2015 by meena.p

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But-1-ene $\to$ ? the product in the above reaction is ?

asked Dec 8, 2015 by meena.p

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End product of the following reaction is $CH_3CH_2COOH \to alcoholic KOH$

asked Dec 8, 2015 by meena.p

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Alkyl Fluorides are synthesised by heating an alkyl chloride / bromide in presence of - or -

asked Dec 8, 2015 by meena.p

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Alkyl halides are prepared from alcohols by treating with

asked Dec 8, 2015 by meena.p

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Which of the following are secondary bromides ?

asked Dec 7, 2015 by meena.p

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Which of the following compounds are g.m dihalide ?

asked Dec 7, 2015 by meena.p

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Reaction of $C_6H_5CH_2Br$ with aqueous sodium hydroxide follows _____________

asked Dec 7, 2015 by meena.p

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The position of Br in the compound in $CH_3CH = CHC(Br)(CH_3)_2$ can be classofied

asked Dec 7, 2015 by meena.p

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Which of the following are benzylic alcohols ?

asked Dec 7, 2015 by meena.p

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Phenol can be distinguished from ethnal by the reaction with ___________

asked Dec 7, 2015 by meena.p

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