Recent questions tagged 2012

Deficiency of vitamin $B_1$ causes the disease

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Among the following compounds the one that is most reactive towards electrophilic nitration is :

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Which nomenclature is not according to IUPAC system ?

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In the following reaction : The major product is :

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The correct order of decreasing acid strength of trichloroacetic acid (A), trifluoroacetic acid (B), acetic acid (C) and formic acid (D) is :

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Which one of the alkali metals, forms only, the normal oxide, $M_2O$ on heating in air ?

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Which one of the following is a mineral of iron ?

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Bond order of 1.5 is shown by:

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The pair of species with the same bond order is

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Identify the alloy containing a non-metal as a constituent in it.

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Which of the following statements is not valid for oxoacids of phosphorus ?

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Identity the wrong statement in the following

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In the extraction of copper from its sulphide ore, the metal is finally obtained by the reduction of cuprous oxide with :

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Equimolar solutions of the following substances were prepared separately. Which one of these will record the highest pH value ?:

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The ease of adsorption of the hydrated alkali metal ions on an ion-exchange resins follows the order :

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Which one of the following is an outer orbital complex and exhibits paramagnetic behaviour :

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A mixture of potassium chlorate, oxalic acid and sulphuric acid is heated. During the reaction which element undergoes maximum change in the oxidation number ?

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Which of the statements is not true ?

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Aluminium is extracted from alumina $(Al_2O_3)$ by electrolysis of a molten mixture of :

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In which of the following compounds, nitrogen exhibits highest oxidation state ?

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The enthalpy of fusion of water is $1.435 \frac{kcal}{mol}$. The molar entropy change for the melting of ice at $0^{\circ}C$ is :

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A metal crystallizes with a face-centered cubic lattice. The edge of the unit cell is 408 pm. The diameter of the metal atom is

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The correct set of four quantum numbers for the valence electron of rubidium atom (Z = 37) is

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The number of octahedral void(s) per atom present in a cubic close-packed structure is :

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Standard enthalpy of vapourisation $\bigtriangleup _{vap}H^{\ominus}$ for water at 100°C is $40.66 kJ mol^{-1}$. The internal energy of vaporisation of water at 100°C (in $kJmol^{-1}$) is :

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50 mL of each gas A and of gas B takes 150 and 200 seconds respectively for effusing through a pin hole under the similar conditions. If molecular mass of gas B is 36, the molecular mass of gas A will be ?

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Maximum number of electrons in a subshell with l = 3 and n = 4 is :

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The protecting power of lyophilic colloidal sol is expressed in term of

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$P_A$ and $P_B$ are the vapour pressure of pure liquid components, A and B, respectively of an ideal binary solution. If $X_A$ represents the mole fraction of component A, the total pressure of the solution will be:

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Which one of the following statements is incorrect about enzyme catalysis ?

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When $Cl_2$ gas reacts with hot and concentrated sodium hydroxide solution, the oxidation number of chlorine changes from :

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pH of a saturated solution of $Ba(OH)_2 $ is 12. The value of solubility product $(K_{SP}) of Ba(OH)_2$ is

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In Freundlich Adsorption isotherm, the value of $\frac{1}{n}$ is :

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Buffer solutions have constant acidity and alkalinity because

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Which of the following species contains three bond pairs and one lone pair around the central atoms ?

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Limiting molar conductivity of $NH_4OH$ (i.e. $\Lambda^o_m (NH_4 OH))$ is equal to

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In a reaction, $A + B \rightarrow Product $, rate is doubled when the concentration of B is doubled, and rate increases by a factor of 8 when the concentrations of both the reactants (A and B) are doubled, rate law for the reaction can be written as

asked Aug 20, 2018 by pady_1

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In which of the following reactions, standard reaction entropy change $(\Delta S°)$ is positive and standard gibb's energy change $(\Delta G°)$ decreases sharply with increasing temperature ?

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Which one of the following pairs is isostructural (i.e. having the same shape and hybridization) ?

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In a zero-order reaction for every 10° rise of temperature, the rate is doubled. If the temperature is increased from 10°C to 100°C, the rate of the reaction will become:

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Transfer characteristics [output voltage $(V_0)$ vs input voltage $(V_i)$] for a base biased transistor in CE configuration is as show in the figure. For using transistor as a switch, it is used.

asked Aug 20, 2018 by pady_1

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C and Si both have same lattice structure, having 4 bonding electrons in each. However, C is insulator where as Si is intrinsic semiconductor. This is because.

asked Aug 20, 2018 by pady_1

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In a CE transistor amplifier, the audio singal voltage across the collector resistance of $2k\Omega$ is 2V. If the v base resistance is $1 k\Omega$ and the current amplification of the transistor is 100, the input signal voltage is

asked Aug 20, 2018 by pady_1

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The figure shown a logic circuit with two inputs A and B and the output C. The voltage wave farms across A, B and C are given. The logic circuit gate is

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Two ideal diodes are connected to a battery as shown in the circuit. The current supplied by the battery is

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A mixture consists of two radioactive materials $A_1$ and $A_2$ with half lives of $20\; s$ and $10\;s$ respectively. Initially the mixture has $40 \;g$ of $ A_1$ and $160\; g$ of $A_2$. The amount of the two in the mixture will become equal after :

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If the nuclear radius $of^{27}$ Al is 3.6 Fermi, the approximate nuclear radius $of ^{64}$ Cu in Fermi is

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An electron of a stationary hydrogen atom passes from the fifth energy level to the ground level. The velocity that the atom acquired as a result of photon emission will be

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Electron in hydrogen atom first jumps from third excited state to second excited state and then from second excited to the first excited state. The ratio of the wavelengths $\lambda_1 : \lambda_2$ emitted in the two cases is

asked Aug 20, 2018 by pady_1

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A 200 W sodium street lamp emits yellow light of wavelength $0.6 \mu m$. Assuming it to be 25% efficient in converting electrical energy to light, the number of photons of yellow light it emits per second is .

asked Aug 20, 2018 by pady_1

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