Recent questions tagged medium

How much heat would release when an aqueous solution containing 0.5 mol of $HNO_3$ is mixed with 0.3 mol of $OH^{-1}$? Given, enthalpy of neutralisation is -57.1 kJ.

asked Feb 26, 2014 by mosymeow_1

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The compound , whose stereo-chemical formula is written below exhibits x geometrical isomers and y optical isomers.

asked Feb 26, 2014 by meena.p

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In the below sequence X and Y are

asked Feb 26, 2014 by sreemathi.v

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Out of the following , the one containing only nucleophiles is

asked Feb 26, 2014 by meena.p

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Which of the following compound observed in the mechanism of Beckmann rearrangement of the below

asked Feb 26, 2014 by sreemathi.v

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What is the change in entropy of 1 mole of a perfect gas, which expands isothermally to ten times its original volume?

asked Feb 26, 2014 by mosymeow_1

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Show the relation between the enthalpies of the reactions: $H_2(g)+ \frac{1}{2} O_2(g) \rightarrow H_2O(g); \Delta H_1$ and $H_2(g)+\frac{1}{2}O_2(g) \rightarrow H_2O(l); \Delta H_2$

asked Feb 25, 2014 by mosymeow_1

1 answer

An organic compound A upon reacting with $NH_3$ gives B. On heating B gives C. C in presence of $KOH$ reacts with $Br_2$ to give $CH_3CH_2NH_2$ A is :

asked Feb 25, 2014 by meena.p

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The following table lists the bond dissociation energy ($E_{diss}$) for single covalent bonds formed between C and atoms A, B, D, E. Which of the atoms has smallest size?

asked Feb 25, 2014 by mosymeow_1

1 answer

The IUPAC name of the compound :$CH_2 =CH-CH(CH_3)_2$

asked Feb 25, 2014 by meena.p

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Consider the following statements \[\] Statement 1: The energy of a charged particle does not change in spatially varying magnetic field \[\] Statement 2: The instantaneous work done by magnetic field is zero

asked Feb 25, 2014 by thanvigandhi_1

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Masses of two isobars $\;_{29}^{64}Cu\;$ and $\;_{30}^{64}Zn\;$ are 63.9298n and 63.9292n respectively.It can be concluded from these data that

asked Feb 25, 2014 by yamini.v

1 answer

A straight wire of length $\ell$ carries a current $i$. The magnitude of magnetic field at the point $P$ is

asked Feb 25, 2014 by thanvigandhi_1

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The IUPAC name of the compound

asked Feb 25, 2014 by meena.p

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Which of the following represents the given mode of hybridisation $Sp^2-Sp^2-Sp-Sp$ from left to right?

asked Feb 25, 2014 by meena.p

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A monochromatic radiation wavelength $\;\lambda_{1}\;$ is incident on a stationary atom as a result of which wavelength of photon after collision becomes $\;\lambda_{2}\;$ and recoiled atom has De- Broglie's wavelength $\;\lambda_{3}\;$.Then

asked Feb 25, 2014 by yamini.v

1 answer

A metal M(at.wt = 40.0) depending on temperature crystallises in f.c.c and b.c.c structure whose unit cell length are 3.5 and $3.0 A^{\large\circ}$ respectively. The ratio of its densities in f.c.c and b.c.c structures is

asked Feb 25, 2014 by sharmaaparna1

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If a stationary electron gets annihilated due to association with a stationary positron (hypothetically), the wavelength of resulting radiation will be .

asked Feb 25, 2014 by yamini.v

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Which of the following is expected to have the lowest boiling point?

asked Feb 25, 2014 by sreemathi.v

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The density of KBr is 2.73g/cm. The length of the unit cell is 654pm. Find the number of atoms per unit cell in the cubic structure.

asked Feb 25, 2014 by sharmaaparna1

1 answer

Find the co-ordination number of sodium in $Na_2O$.

asked Feb 25, 2014 by sharmaaparna1

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Acid-catalysed reaction of oxirane is given below:

asked Feb 25, 2014 by sreemathi.v

1 answer

In CsCl with cubic structure $Cl^-$ ions are located at each corner and $Cs^+$ ions at the centre of the unit cell. If $r_{Cs^+}$ and $r_{Cl^-}$ are $1.69A^{\large\circ}$ and $1.81A^{\large\circ}$ respectively . Find the value of edge length of cube.

asked Feb 25, 2014 by sharmaaparna1

1 answer

When a metallic surface is illuminated with monochromatic light of wavelength $\;\lambda\;$ and stopping potential for photo electron current is $\;3V_{0}\;$ . When some metallic surface is illuminated with a light of wavelength $\;2 \lambda\;$ , The stopping potentials is $\;V_{0}\;$ . The threshold wavelength for surface is

asked Feb 25, 2014 by yamini.v

1 answer

In the below reaction product is/are

asked Feb 25, 2014 by sreemathi.v

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A photon of wavelength $\;5030 A^{0}\;$ is incident on a totally reflecting surface. The momentum delivered by photon is equal to

asked Feb 25, 2014 by yamini.v

1 answer

The formation of peroxide linkage in either due to the exposure in air can be detected by treating in with

asked Feb 25, 2014 by sreemathi.v

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What are the resulting products of the reaction below?

asked Feb 25, 2014 by sreemathi.v

1 answer

Tautomerism is exhibited by

asked Feb 25, 2014 by meena.p

1 answer

Dipole moment is shown by (i) 1,4 dichlorobenzene (ii) cis-1,2-dichloroethane. (iii) trans -1,2- dichleroethene (iv) trans-1,2- dichloro-2-pentene.

asked Feb 25, 2014 by meena.p

1 answer

The difference between any two consecutive interior angles of a polygon is $5^\circ$. If the smallest angle is $120^ \circ$, then find the number of sides of the polygon.

asked Feb 24, 2014 by rvidyagovindarajan_1

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For the reaction between $CO_2$ and graphite $CO_2(g) + C(s) \longrightarrow 2CO(g)$ $\Delta H = +170.0 kJ$ and $\Delta S = 170 JK^{-1}$. The reaction is spontaneous at

asked Feb 24, 2014 by mosymeow_1

1 answer

Phenol is less acidic than (i) acetic acid (ii) p-methoxyphenol (iii) p- nitrophenol (iv) ethanol

asked Feb 24, 2014 by meena.p

1 answer

An engine operating between $100^\circ C$ and $0^\circ C$ takes 453.6 Kcal of heat. How much useful work can be done by it?

asked Feb 24, 2014 by mosymeow_1

1 answer

If $\large\frac{a^n+b^n}{a^{n-1}+b^{n-1}}$ is the $A.M.$ between $a$ and $b$, then find the value of $n$

asked Feb 24, 2014 by rvidyagovindarajan_1

1 answer

For the gaseous reaction involving the complete combustion of isobutane

asked Feb 24, 2014 by mosymeow_1

1 answer

The weight based ratio of $\;U^{238}\;$ and $\;Pb^{226}\;$ in a sample of rock is 413 . if the half life of $\;u^{238}\;$ is $\;4.5 \times10^{9}\;years \;,$ then age of rock is

asked Feb 24, 2014 by yamini.v

1 answer

A hydrogen atom is in an excited state of principal quantaum number$\; (n)\;$ it emits a photon of wavelength $\;(\lambda)\;,$ when it returns to ground state . The value of n is

asked Feb 24, 2014 by yamini.v

1 answer

There are two radioactive substance A and B . Decay constant of B is two times that of A . Initially both have equal no.of nuclei . After n Lay liver of A rate of disintegration of both are equal . The value of n is

asked Feb 24, 2014 by yamini.v

1 answer

The ratio of minimum to maximum wavelengths of radiation that an electron cause in Bohr's hydrogen atom is

asked Feb 24, 2014 by yamini.v

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Ice crystallizes in hexagonal lattice. At the low temperature at which structure was determined the lattice constants were $a = 4.53A^{\large\circ}$ and C = $b = 7.41A^{\large\circ}$ .Calculate the no. of $H_2O$ molecules present in a unit cell. (Density of ice = 0.92g/cm)

asked Feb 24, 2014 by sharmaaparna1

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A compound $AB_x$ is formed such that A atoms are at corners and B atoms at face centre. Find the value of $x$ .

asked Feb 24, 2014 by sharmaaparna1

1 answer

The mean lives of an radio active substance are 1620 and 405 years for $\;\alpha-\;$emission and $\;\beta-\;$ emission respee. Find out time during which three fourth of a sample will decay if it is decaying both the $\;\alpha-\;$emission and $\;\beta-\;$ emission simultaneously

asked Feb 24, 2014 by yamini.v

1 answer

A molecule $A_2B$(mol.weight = 166.4) occupies triclinic lattice with a = 5A , b = 8A and C = 4A . If density of $AB_2$ is $5.2g cm^{-3}$. Calculate the number of molecules present in one unit cell.

asked Feb 24, 2014 by sharmaaparna1

1 answer

uranium ores on earth at present time typically have a composition of $\;99.3 \%$ of isotope $\;_{92}U^{238}\;$ and $\;0.7 \%\;$ of isotope $\;_{92}U^{235}\;$. The half lives of these isotopes are $\;4.47 \times10^{9}y\;$ and $\;7.04\times10^{8}y\;$ respectively . If these isotopes were equally abundent when the earth was formed , estimate the age of earth .

asked Feb 24, 2014 by yamini.v

1 answer

A deuterium reaction that occurs in an experimental fusion reactor is in two stapes \[\] (1) Two deuterium nucli fuse together to form a tritium nucleus , with a proton as a by-product written as $\; 1 > (D ,P)\; T\;.$ \[\] (2) A tritium nucleus fuses with another oleunterium nucleus to form a helium $\;_{2}He^{4}\;$ nucleus with neutron as a-by-product written as $\;T (D,n)\;_{2}He^{4}\;.$ Then the energy released in each of two stages and energy released in combined reaction is \[\] Given \[\] $\;_{1}D^{2}=2.014102\;a.m.u $ \[\] $\;_{1}T^{3}=3.016049\;a.m.u$ \[\] $\;_{1}H^{1}=1.007825\;a.m.u$ \[\] $\;_{1}n^{1}=1.008665\;a.m.u$\[\] The energy released per deuterium nuclei is

asked Feb 24, 2014 by yamini.v

1 answer

A deuterium reaction that occurs in an experimental fusion reactor is in two stapes \[\] (1) Two deuterium nucli fuse together to form a tritium nucleus , with a proton as a by-product written as $\; 1 > (D ,P)\; T\;.$ \[\] (2) A tritium nucleus fuses with another oleunterium nucleus to form a helium $\;_{2}He^{4}\;$ nucleus with neutron as a-by-product written as $\;T (D,n)\;_{2}He^{4}\;.$ Then the energy released in each of two stages and energy released in combined reaction is \[\] Given \[\] $\;_{1}D^{2}=2.014102\;a.m.u $ \[\] $\;_{1}T^{3}=3.016049\;a.m.u$ \[\] $\;_{1}H^{1}=1.007825\;a.m.u$ \[\] $\;_{1}n^{1}=1.008665\;a.m.u$

asked Feb 24, 2014 by yamini.v

1 answer

The number of isomers for the compound with molecular $C_2BrClFI$ is :

asked Feb 24, 2014 by meena.p

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A cylinder container with the moveable piston initially hold 3.0 mole of a gas at 8.0 atm pressure and a volume of 5.0 litre. If piston is moved to create a volume 10.0 litre , while simultaneously with drawing 1.5 mole of gas. Calculate the final pressure.

asked Feb 23, 2014 by sharmaaparna1

1 answer

X gm of ethanal was subjected to combustion in a bomb calorimeter. The heat produced is Y joules. Then

asked Feb 23, 2014 by mosymeow_1

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