Recent questions tagged 2003

IUPAC name of the compound given below is :

asked Jul 24, 2018 by pady_1

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The temperature dependence of rate constant $(k)$ of a chemical reaction is written in terms of Arrhenius equation, $k = A.e^{–E^/RT}$. Activation energy $(E^)$ of the reaction can be calculated by plotting

asked Jul 24, 2018 by pady_1

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The molar heat capacity of water at constant pressure, C, is $75 \;JK^{–1} mol^{–1}$. When 1.0 KJ of heat is supplied to 100 g of water which is free to expand, the increase in temperature of water is :

asked Jul 24, 2018 by pady_1

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The molar heat capacity of water at constant pressure, C, is $75 \;JK^{–1} mol^{–1}$. When 1.0 KJ of heat is supplied to 100 g of water which is free to expand, the increase in temperature of water is :

asked Jul 24, 2018 by pady_1

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The following equilibria are given : <img src = ""/>

asked Jul 24, 2018 by pady_1

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For which one of the following equations is $\Delta H^{\circ}_{react}$ equal to $\Delta H^o_f$ for the product :

asked Jul 24, 2018 by pady_1

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Formation of a solution from two components can be considered as : (i) Pure solvent $\to$ separated solvent molecules, $ \Delta H_1$ (ii) Pure solvent $\to$ separated solvent molecules, $ \Delta H_2$ (iii) Separated solvent and solute molecules $\to$ solution, $\Delta H_3$ Solution so formed will be ideal if : -

asked Jul 24, 2018 by pady_1

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The solubility product of AgI at $25^oC$ is $1.0 \times 10^{–16} mol^2 L^{–2}$. The solubility of AgI in $10^{–4} N$ solution of KI at $25^oC$ is approximately (in $mol\; L^{–1}$) :

asked Jul 24, 2018 by pady_1

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The reaction A $\to$ B follows first order kinetics. The time taken for 0.8 mole of A to produce 0.6 mole of B is 1 hour. What is the time taken for conversion of 0.9 mole of A to produce 0.675 mole of B

asked Jul 24, 2018 by pady_1

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On the basis of the information available from the reaction : $\frac{4}{3} Al + O_2 \to \frac{2}{3} Al_2O_3, \Delta G = -827 \;KJ \; mol^{-1}$ of $O_2$, the minimum e.m.f required to carry out electrolysis of $Al_2O_3$ is $(F = 96500 \; C\; mol^{-1})$

asked Jul 24, 2018 by pady_1

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The method of zone refining of metals is based on the principle of :

asked Jul 24, 2018 by pady_1

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Which of the following statements is not true :

asked Jul 24, 2018 by pady_1

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The activation energy for a simple chemical reaction $A \to B$ is $E_a$ in forward direction. The activation energy for reverse reaction :

asked Jul 24, 2018 by pady_1

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The reaction quotient (Q) for the reaction : <img src =""/> is given by $Q = \frac{[NH_3]^2}{[N_2] [H_2]^3}$. The reaction will proceed from right to left if : (where $K_C$ is the equilibrium constant )

asked Jul 24, 2018 by pady_1

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What is the entropy change (in $JK^{–1} mol^{–1}$) when one mole of ice is converted into water at $0^oC$ ? (The enthalpy change for the conversion of ice to liquid water is $6.0 \;KJ\; mol^{–1}\; at \;0^oC$)

asked Jul 24, 2018 by pady_1

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The densities of graphite and diamond at $298 K$ are $2.25$ and $3.31 g\; cm^{–3}$, respectively. If the standard free energy difference ($\Delta G^o$) is equal to $1895 J \;mol^{–1}$, the pressure at which graphite will be transformed into diamond at $298 K$ is -

asked Jul 24, 2018 by pady_1

2 answers

In Haber process 30 litres of dihydrogen and 30 litres of dinitrogen were taken for reaction which yielded only 50% of the expected product. What will be the composition of gaseous mixture under the above condition in the end :

asked Jul 24, 2018 by pady_1

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For the reaction : $C_3H_8(g) + 5O_2 (g) \to 3CO_2(g) + 4H_2O(l)$ at constant temperature, $\Delta H - \Delta E$ is :

asked Jul 24, 2018 by pady_1

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The pyknometric density of sodium chloride crystal is $2.165 \times 10^3 kg\; m^{–3}$ while its X-ray density is $2.178 \times 10^3 kg \; m^{–3}$. The fraction of unoccupied sites in sodium chloride crystal is :

asked Jul 24, 2018 by pady_1

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The oxidation states of sulphur in the anions $SO_3^{2–}, S_2O_4^{2–}$ and $S_2O_6^{2–}$ follow the order -

asked Jul 24, 2018 by pady_1

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Which of the following statements is not correct for sigma- and pi- bonds formed between two carbon atoms :

asked Jul 24, 2018 by pady_1

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The value of Planck's constant is $6.63 \times 10^{–34}Js$. The velocity of light is $3.0 \times 10^8 ms^{–1}$. Which value is closest to the wavelength in nanometers of a quantum of light with frequency of $8 \times 10^{15} s^{–1}$ :

asked Jul 24, 2018 by pady_1

2 answers

Which one of the following compounds is not a protonic acid :

asked Jul 24, 2018 by pady_1

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The ions $O^{2-} , F^-, Na^+, Mg^{2+}$ and $Al^{3+}$ are isoelecronic. Their ionic radii show :

asked Jul 24, 2018 by pady_1

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Following diagram performs the logic function of :

asked Jul 24, 2018 by pady_1

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A nuclear reaction given by $_ZX^A \to _{Z + 1}Y^A + _{–1}e ^0 + \overline{v}$ represents

asked Jul 24, 2018 by pady_1

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The mass number of a nucleus is

asked Jul 24, 2018 by pady_1

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The mass of proton is 1.0073 u and that of neutron is 1.0087 u (u = atomic mass unit). The binding energy of $^4_2He$ is (Given : helium nucleus mass ≈ 4.0015 u)

asked Jul 24, 2018 by pady_1

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Barrier potential of a p-n junction diode does not depend on -

asked Jul 24, 2018 by pady_1

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If a full wave rectifier circuit is operating from 50 Hz mains, the fundamental frequency in the ripple will be :

asked Jul 24, 2018 by pady_1

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Diamagnetic material in a magnetic field moves :

asked Jul 24, 2018 by pady_1

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According to Curie's law, the magnetic susceptibility of a substance at an absolute temperature T is proportional to -

asked Jul 24, 2018 by pady_1

2 answers

A n-p-n transistor conducts when

asked Jul 24, 2018 by pady_1

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Which of the following ray are not electromagnetic waves

asked Jul 24, 2018 by pady_1

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J.J. Thomson's cathode-ray tube experiment demonstrated that

asked Jul 24, 2018 by pady_1

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Reverse bias applied to a junction diode

asked Jul 24, 2018 by pady_1

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In which of the following systems will be radius of the first orbit (n = 1) be minimum -

asked Jul 24, 2018 by pady_1

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A sample of radioactive element has a mass of 10 gm at an instant t = 0. The approximate mass of this element in the sample after two mean lives is :

asked Jul 24, 2018 by pady_1

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A photoelectric cell is illuminated by a point source of light 1 m away. When the source is shifted to 2m then -

asked Jul 24, 2018 by pady_1

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The volume occupied by an atom is greater than the volume of the nucleus by a factor of about

asked Jul 24, 2018 by pady_1

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Fuse wire is a wire of

asked Jul 24, 2018 by pady_1

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Solar energy is mainly caused due to :

asked Jul 24, 2018 by pady_1

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Three capacitors each of capacity $4 \mu F$ are to be connected in such a way that the effective capacitance of $6 \mu F$. This can be done by -

asked Jul 24, 2018 by pady_1

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In a Wheatstone's bridge all the four arms have equal resistance R. If the resistance of the galvanometer arm is also R, the equivalent resistance of the combination as seen by the battery is :

asked Jul 24, 2018 by pady_1

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An electric kettle has two heating coils. When one of the coils is connected to an a.c. source, the water in the kettle boils in 10 minutes. When the other coil is used the water boils in 40 minutes. If both the coils are connected in parallel, the time taken by the same quantity of water to boil will be :-

asked Jul 24, 2018 by pady_1

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Two 220 volt, 100 watt bulbs are connected first in series and then in parallel. Each time the combination is connected to a 220 volt a.c. supply line. The power drawn by the combination in each case respectively will be :

asked Jul 24, 2018 by pady_1

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A bar magnet is oscillating in the Earth's magnetic field with a period T. What happens to this period and motion if this mass is quadrupled -

asked Jul 24, 2018 by pady_1

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A charged particle moves through a magnetic field in a direction perpendicular to it. Then the

asked Jul 24, 2018 by pady_1

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A long solenoid carrying a current produces a magnetic field B along its axis. If the current is doubled and the number of turns per cm is halved, the new value of the magnetic field is -

asked Jul 24, 2018 by pady_1

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An electron is moving round the nucleus of a hydrogen atom in a circular orbit of radius r. The coulomb force $\overrightarrow{F}$ between the two is - (where $K = \frac{1}{4 \pi \varepsilon_0}$ )

asked Jul 24, 2018 by pady_1

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