Recent questions in Chemistry

State the uses of carboxylic acids :

asked Oct 31, 2016 by meena.p

1 answer

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

asked Oct 31, 2016 by meena.p

1 answer

What happens when bromine reacts with $CH_3 - C = CH$? How would you justify this reaction ?

asked Oct 27, 2016 by meena.p

1 answer

(i) Why do compounds having similar geometry have different magnetic moment ? (ii)$FeSO_4$ solution mixed with $(NH_4)_2SO_4$ solution in 1 : 1 molar ratio gives the test of $Fe^{2+}$ ion but $CuSO_4$ solution mixed with aqueous ammonia in 1 : 4 molar ratio does not give the test of $Cu^{2+}$ ion. Explain why ?

asked Oct 27, 2016 by meena.p

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What is meant by disproportionation of an oxidation state ? Give an example

asked Oct 27, 2016 by meena.p

1 answer

Give the reasons for the following : (a) $CN^{-}$ ions is known but $CP^{-} $ ion is not known (b) $NO_2$ dimerizes to form $N_2O_4$ (c) $ICI$ is more reactive that $I_2$

asked Oct 27, 2016 by meena.p

1 answer

Out of C and CO, which is a better reducing agent for ZnO ?

asked Oct 27, 2016 by meena.p

1 answer

Nitric oxide $NO,$ reacts with oxygen to produce nitrogen dioxide $2 NO(g)+O_2(g) \to 2NO_2(g)$ The rate law for this reaction is : $Rate = k[NO]^2 [O_2]$ Propose a mechanism for the reaction.

asked Oct 27, 2016 by meena.p

1 answer

Account for the following : (i) Alkaline medium inhibits rusting of iron . (ii) Iron does not rust even if the zinc coating is broken in a galvanized iron pipe.

asked Oct 27, 2016 by meena.p

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Why a person suffering from high blood pressure is advised to take minimum quantity of common salt

asked Oct 26, 2016 by meena.p

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If the radius of the octahedral void is r and the radius of the atoms in the close packing is R, derive relationship between r and R.

asked Oct 26, 2016 by meena.p

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Write chemical equation for the following conversions : (i) Nitro benzene to benzoic acid. (ii) Benzyl chloride to 2-phenylethanamine. (iii) Aniline to benzyl alcohol .

asked Oct 26, 2016 by meena.p

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What type of a battery is the lead storage battery ? write the anode and the cathode reaction occurring in a lead storage battery when current is drawn from it .

asked Oct 26, 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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How would you obtain (i) Picric acid (2,4,6- trinitrophenol) from phenol (ii) 2- Methyl propene from 2- Methyl propanol ?

asked Oct 26, 2016 by meena.p

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Predict which of the following will be colourless in aqueous solution ? $Ti^{3+},V^{3+},Sc^{3+},Mn^{2+},Fe^{3+},Co^{2+}$ and $MnO_4^{-}$

asked Oct 26, 2016 by meena.p

1 answer

Resistance of a conductivity cell filled with $0.1\;mol L^{-1}KCl$ solution is $100\;\Omega$ . If the resistance of the same cell when filled with $0.02\;molL^{-1}\;KCl$ Solution . The conductivity of $0.02\;mol L^{-1}KCl$ Solution . The conductivity of $0.1\;mol\;L^{-1}$ Solution is $1.29\;s/m$

asked Oct 26, 2016 by meena.p

1 answer

Why is osmotic pressure of $1\;M\;KCl$ higher than $1\;M$ urea solution ?

asked Oct 26, 2016 by meena.p

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What type of defect can arises when a solid is heated ? Which physical properly is affected by it and in what way ?

asked Oct 26, 2016 by meena.p

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Why is drug metabolism a major consideration in drug design ?

asked Oct 25, 2016 by meena.p

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How does vulcanization change the properties of natural rubber ?

asked Oct 25, 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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Do we call metal carbonyls as organometallics ? Why or why not ?

asked Oct 25, 2016 by meena.p

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Give one example each of oil in water and water in oil emulsion.

asked Oct 25, 2016 by meena.p

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(a)The rate constant for a reaction of zero order in A is $0.0030\;mol L^{-1}S^{-1}$ How long will it take for the initial concentration of A to fall from $0.10\;M$ to $0.075\;M$ ? (b)What type of colloidal sols are formed in the following : (i) Sulphur vapours are passed through colled water (ii) White of an egg is mixed with water . (iii) Soap solution

asked Oct 25, 2016 by meena.p

1 answer

Why does a galvanic cell become dead after some time ?

asked Oct 25, 2016 by meena.p

1 answer

Aluminium crystallizes in a cubic - packed structure . Radius of the atom in the metal is $125\;pm$ (i) What is the length of the side of the unit cell ? (ii) How many unit cells are there in $1\;cm^3$ of aluminium ?

asked Oct 25, 2016 by meena.p

1 answer

What is the nature of an antacid ?

asked Oct 25, 2016 by meena.p

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Write the information asked in the following polymers: (i) Bakelite -Materials used for preparation (ii) Nylon -6,6-Material required for preparation (iii) Synthetic rubber - monomeric repeating unit (iv) PVC - Monomeric repeating unit

asked Oct 24, 2016 by meena.p

1 answer

Draw the structure of $BrF_3$ molecule

asked Oct 24, 2016 by meena.p

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The second and third rows of transition elements resemble each other much more than they resemble the first row. explain why ?

asked Oct 24, 2016 by meena.p

1 answer

write the disproportionate reaction of that oxoacids of nitrogen in which nitrogen is in +3 oxidation state .

asked Oct 24, 2016 by meena.p

1 answer

What type of colloidal sols are formed in the following : (i) Sulphur vapours are passed through colled water (ii) White of an egg is mixed with water . (iii) Soap solution

asked Oct 24, 2016 by meena.p

1 answer

(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

1 answer

Give chemical reactions for the following observations: (i) Potassium permanganate is a good oxidising agent in basic medium. (ii) Inter-convertibility of chromate ion and dichromate ion in aqueous solution depends upon pH of the solution . (iii) Potassium permanganate is thermally unstable at 513 K

asked Oct 24, 2016 by meena.p

1 answer

(i)What is the freezing point of $0.4 $ molal solution of acetic acid in benzene in which it dimerises to the extent of $85\%$ Freezing point of benzene is $278.4 \;k$ and its molar heat of fusion is $10.042\;kj\; mol^{-1}$ (ii) Write balanced chemical equation for the following reactions : (a) Thermal decomposition of ammonium dichromate. (b) Reaction of $Cl_2$ with cold and deleted NaOH (c) When phosphine is passed through mercuric chloride solution .

asked Oct 24, 2016 by meena.p

1 answer

The resistance of the conductivity cell containing $0.001\;M\;KCl$ solution at $298\;K$ is $1500\Omega$. What is the cell constant if conductivity of $0.001\;M\;KCl$ solution at $298\;K$ is $0.14 \times 10^{-3} 5\;cm^{-1}? $

asked Oct 21, 2016 by meena.p

1 answer

Differentiate between morality and molality of a solution . Explain how molality value of a solution can be converted into its molality

asked Oct 21, 2016 by meena.p

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(a)What changes occurs in the nature of egg protein on boiling ? (b) Name the type of bonding . Which stabilizes $\alpha - helix$ structure in proteins .

asked Oct 21, 2016 by meena.p

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Out of $H_2O$ and $H_2S$ which one has higher, bond angle ?

asked Oct 21, 2016 by meena.p

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Explain the role of (a) Cryolite in the electrolytic reduction of alumina . (b) carbon monoxide in the purification of nickel

asked Oct 21, 2016 by meena.p

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Why does a solution of ethanol and cyclohexane show positive deviation from Raoult's law?

asked Oct 21, 2016 by meena.p

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A compound is formed by two elements, M and N . The element N forms CCP and atoms of M occupy $\large\frac{1}{3}$ rd of tetrahedral voids . What is the formula of the compound?

asked Oct 21, 2016 by meena.p

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a)How would you explain the amphoteric behavior of amino acids b) How does vulcanization change the properties of natural rubber ? (b)Explain what is meant by : (i) a peptide linkage (ii) a glycosidic linkage ?

asked Oct 21, 2016 by meena.p

1 answer

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

asked Oct 21, 2016 by meena.p

1 answer

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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Write the IUPAC name of $(i) [Fe(CN)_6]^{3-} \\ (ii) [CoCl_2(en)_2]Cl$

asked Oct 21, 2016 by meena.p

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Why does physiorption decrease with increase of temperature ?

asked Oct 20, 2016 by meena.p

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Name one substance which can act as both (i) Analgesic and Antipyretic (ii) Antiseptic and disinfectant

asked Oct 20, 2016 by meena.p

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On dissolving $19.5\;g$ of $CH_2FOOH$ in $500\;g$ of water, a depression of $1^{\circ}C$ in freezing point of water is observed . Calculate the van't Hoff factor and dissociation constant of fluoro acetic acid Given $K_f= 1.86\;k kg mol^{-1}$

asked Oct 20, 2016 by meena.p

1 answer

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