Recent questions tagged sec-c

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

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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

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

asked Oct 24, 2016 by meena.p

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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

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

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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

1 answer

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

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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

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Write (a) Reaction involved in the preparation of a biodegradable polyester. (b) Monomer unit of synthetic rubber (neoprene) (c) One use of Nylon -6,6

asked Oct 20, 2016 by meena.p

1 answer

Describe a chemical test in each case to distinguish between the following pairs of compounds. (a) Aniline and N-ethyl aniline (b) N- methyl propane -2 amine and N-ethyl methyl ethanamine

asked Oct 20, 2016 by meena.p

1 answer

Justify the following (a)(i) Sleeping pills are recommended to patient suffering from sleepless but it is not adorable to take them without consulting the doctor . (ii) Why do we require artificial sweetening agents (b) Write the composition of Dettol

asked Oct 20, 2016 by meena.p

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(a) Give one reaction of D- glucose which cannot be explained by its open chain structure . (b)Give one example each for essential and non essential amino acids (c) Differentiate between keratin and insulin .

asked Oct 20, 2016 by meena.p

1 answer

Account for the following : (a) Chloro methane reacts with KCN to form ethanenitrile as main product and with $AgCN$ to form methyl isocyanide as chief product . (b) Chloroform should be stored in dark coloured bottles and these bottle should be completely filled .

asked Oct 19, 2016 by meena.p

1 answer

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 19, 2016 by meena.p

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Out line the principle of the method used for refining of (a)Nickel (b)Zirconium (c) Tin

asked Oct 19, 2016 by meena.p

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Give reasons for the following observation : (a) Colloids Stabilize due to Brownian movement . (b) Cornell's smoke precipitation is fixed at the mouth of chimney used in factories. (c) Colloidal gold is used for intramuscular injection .

asked Oct 19, 2016 by meena.p

1 answer

(a) Calculate the charge in coulombs required for oxidation for 2 moles of water to oxygen. [Given $IF= 96,500\;c\;mol^{-1}$] (b) Zinc / Silver oxide cell is used is hearing aids and electric watches . The following reaction occur. $Zn(S) \to Z_n^{2+} (aq)+2e^{-} E^0_{Zn^{2+}/Zn}=-0.76\;V \\ Ag_20+H_2O+2e^{-} \to 2Ag +2 OH - E^0_{Ag^{+}/Ag}=0.344\;V$ Calculate (i) Standard potential of the cell (ii) Standard Gibbs energy .

asked Oct 19, 2016 by meena.p

1 answer

(i) Give names of the reagents to bring about the following transformations. (a) Ethanoic acid to ethanol(b) Propan -1-ol to propanal(c) Pent -3 -en-2-ol to Pent -3-en-2-one(d) Sodium benzonte to benzene(ii) Arrange the following in the increasing order (a) Methanal, propanal, butanone, ethanal , propanone (nucleophilic addition reaction ) (b) Formaldehyde , acetone , acetaldehyde (reactivity towards HCN)(c) Acetophenone , P- toludehyde, p-nitrobenzaldehyde, benzaldehyde (nucleophilic addition reaction )

asked Oct 18, 2016 by meena.p

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Find the differential equation whose general solution is $y= Ae^x+Be^2x+Ce^3x+De^4x+E$ where A,B,C,D,E are constant

asked Oct 17, 2016 by meena.p

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What is the function of sulphur in Vulcanization of rubber ?

asked Oct 17, 2016 by meena.p

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Give Reason The monoamino monocarboxylic acids have two PH values

asked Oct 17, 2016 by meena.p

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How can you separate a mixture of primary , secondary and tertiary amines ? Write chemical reactions involved in the process .

asked Oct 17, 2016 by meena.p

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Predict the product of the following reaction :

asked Oct 17, 2016 by meena.p

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The carbon - oxygen bond in phenol is slightly stronger than that in methanol . Why ?

asked Oct 17, 2016 by meena.p

1 answer

Why do the d - block elements exhibit a large number of oxidation states than f- block elements

asked Oct 17, 2016 by meena.p

1 answer

Copper can be extracted by hydro metallurgy but not zinc. Explain .

asked Oct 17, 2016 by meena.p

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What is the difference between physisorption and chemisorption?

asked Oct 17, 2016 by meena.p

1 answer

Resistance of a conductivity cell filled with $0.1 \;mol^{-1}KCl$ solution is $100 \Omega$ . If the resistance of the same cell when filled with $0.2\;mol L^{-1}\;KCl$ solution is $520\; \Omega$ . Calculate the conductivity of $0.2 mol L^{-1} \;KCl$ solution . The conductivity of $0.1\;mol L^{-1} KCl$ solution is $1.29\;s.m$

asked Oct 14, 2016 by meena.p

1 answer

Alcohols act as weak bases . explain

asked Oct 14, 2016 by meena.p

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Complete the following reactions: $(i) X_eF_6 +H_2O \to$ _+ ___ $\\ (ii) X_eF_6 +H_2O \to$ _ + ___ $ \\ (iii) Cl_2+H_2O \to$ _ + ___

asked Oct 13, 2016 by meena.p

1 answer

A $100 \mu F$ capacitor in series with a $40 \Omega$ resistance is connected to a $110\;v,12\;kHz$ supply's Is the statement that a capacitor is a conductor at very high frequencies . True or false ?

asked Sep 15, 2016 by meena.p

1 answer

A coil of inductance $0.50\;H$ and resistance $100 \Omega$ is connected to a $240\;v,50\;Hz$ a.c supply. If the circuit is connected to a high frequency supply (240 v, 10 kHz) then at very frequency , inductor is that circuit nearly amounts to open circuit. Is this statement true or false ?

asked Sep 15, 2016 by meena.p

1 answer

An LC circuit a $20\;mH$ inductor and a $50 \mu F$ capacitor with an initial charge of $10\;mc$ The resistance of the circuit is negligible. Let the instant the circuit is closed be $t=0$, At what time is the energy stored ? (i) Completely electrical? (ii) Completely magnetic ?

asked Sep 12, 2016 by meena.p

1 answer

An LC circuit a $20\;mH$ inductor and a $50 \mu F$ capacitor with an initial charge of $10\;mc$ The resistance of the circuit is negligible. Let the instant the circuit is closed be $t=0$, What is the natural frequency of the circuit ?

asked Sep 12, 2016 by meena.p

1 answer

An LC circuit a $20\;mH$ inductor and a $50 \mu F$ capacitor with an initial charge of $10\;mc$ The resistance of the circuit is negligible. Let the instant the circuit is closed be $t=0$, What is the total energy stored initially ? Is it conserved during the oscillations ?

asked Sep 12, 2016 by meena.p

1 answer

A series LCR circuit connected to a variable frequency $230\;v$ Source has $L= 5.0\;H,c=80 \mu F,R= 40 \Omega$ as shown in the figure. Determine the r.m.s potential drops across the three elements of the circuit . What is the potential drop across the LC combination at the resonating frequency .

asked Sep 12, 2016 by meena.p

1 answer

A series LCR circuit connected to a variable frequency $230\;v$ Source has $L= 5.0\;H,c=80 \mu F,R= 40 \Omega$ as shown in the figure. obtain the impedance of the circuit and amplitude of current at the resonating frequency.

asked Sep 12, 2016 by meena.p

1 answer

A series LCR circuit connected to a variable frequency $230\;v$ Source has $L= 5.0\;H,c=80 \mu F,R= 40 \Omega$ as shown in the figure

asked Sep 12, 2016 by meena.p

1 answer

A radio can tune over the frequency range of a portion of MW broadcast band (800 kHz to 1200 kHz) If its LC circuit has an effective inductance of $200\;\mu H$, What must be the range of its variable capacitor ?

asked Sep 9, 2016 by meena.p

1 answer

Obtains the maximum kinetic enery of $\beta$ particles and the radiation frequencies of $\gamma$ decays in the delay scheme . You are given that $m(_{79}Au^{198})=197.9682334\;u$$\qquad m(_{80}Hg^{198})=197.966760\;u$

asked Aug 10, 2016 by meena.p

1 answer

A Source contains two phosphors radio nuclides $ _{15}P^{32}(T_{1/2}=14.3\;days)$ and $_{15}P^{33} (T_{1/2} =25.3\;day)$ Initially $10\%$ of the decays come from $_{15}P^{33}$. How long one must wait until $90\%$ do so ?

asked Aug 5, 2016 by meena.p

1 answer

In a periodic table the average atomic mass of magnesium is given as $24.312\;u$ The average value is based on their relative natural abundance on earth. The three isotopes and their masses are $_{12} Mg^{24}(23.98504\;u)$, $_{12} Mg^{25}(24.98584\;u)$ and $_{12} Mg^{24}$ is $78.99\%$ by mass. Calculate the abundances of the other two isotopes.

asked Aug 4, 2016 by meena.p

1 answer

For the $\beta^+$ (positron) emission from a nucleus, there is another competing process known known as electron capture.Electron from an inner orbit is captured by the nucleus and a neutrino is emitted. $\beta^+$ emission is energetically allowed , electron capure is necessarily allowed but not vice- versa . Is this a true statement ?

asked Aug 4, 2016 by meena.p

1 answer

A thousand reactor factor consume half of its fuel in 5.00 y . How much $_{92} U^{235}$ did it contain initially ? Assume that the reactor operates $80\%$ of the time and that all the energy generated arises from the fission of $_{92}U^{235}$ and that this nuclide is consumed by the fission process ?

asked Aug 3, 2016 by meena.p

1 answer

Obtain the binding energy of the nuclei $_{26} Fe^{56}$ and $_{23} Bi ^{209}$ in units of Mev from the following data $m_H= 1.007825\;amu\;m_n= 1.008665\;amu \; m( _{26} Fe ^{56})=55.934939 \;amu\; m( _{83} Fe ^{209})=208.980388 \;amu\;lamu=931.5\;Mev$ Which nucleus has greater binding energy per nucleon ?

asked Jul 11, 2016 by meena.p

1 answer

Using Bohr's model , calculate the orbital period of the electron in a hydrogen atom in the $n= 1,2$ and $3$ levels

asked Jul 6, 2016 by meena.p

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The de- Broglie wave length of a photon is twice the de- Broglie wave length of an electron. The speed of the electron is $v_e = \large\frac{c}{100}$ . Then

asked Jul 4, 2016 by meena.p

1 answer

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