Recent questions tagged chemistry

Which one of the following is a correct set?

asked Oct 21, 2013 by meena.p

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The bond length of HCl molecules is $1.275\;A^{\circ}$ and its dipole moment is $1.03\;D$. The ionic character of the molecule (in percent) (charge of the electron $=4.8 \times 10^{-10}\;e.s.u)$ is

asked Oct 21, 2013 by meena.p

1 answer

The atomic numbers of elements $\underline {A}, \underline {B}, \underline {C}$ and $\underline {D}$ are $z-1,z,z+=1$ and $z+2$ respectively. If '$\underline {B}$' is a noble gas, choose the correct answers from the following statements :

asked Oct 21, 2013 by meena.p

1 answer

If the mass defect of , $B^{11}$ is $0.081\;amu,$ its average binding energy (in Mev) is

asked Oct 21, 2013 by meena.p

1 answer

The velocities of two particles $\underline {A}$ and $\underline {B}$ are $00.05$ and $0.02\;ms^{-1}$ respectively. The mass of $\underline {B}$ is five times the mass of $\underline {A}$. The ratio of their de Broglie's wavelength is

asked Oct 21, 2013 by meena.p

1 answer

An electronic transition in hydrogen atom results, in the formation of $H_{\alpha}$ line of hydrogen in Lyman series, the energies associated with the electron in each of the orbits involved in the transition (in $kCal mol^{-1}$) are

asked Oct 21, 2013 by meena.p

1 answer

The number of lone pairs of electrons on $Xe\: in\: XeF_2, XeF_4\: and \: XeF_6$ are, respectively

asked Oct 20, 2013 by thanvigandhi_1

1 answer

Chlorine reacts with ammonia and gives nitrogen. The ratio of chlorine to ammonia in this reaction is

asked Oct 20, 2013 by thanvigandhi_1

1 answer

One per cent composition of an organic compound $\underline {A}$ is carbon: $85.71 \;\%$ and hydrogen $14.29\; \%$. It's vapour density is 14. Consider the following reaction sequence :

asked Oct 16, 2013 by meena.p

1 answer

What are $\underline{A},\underline {B}, \underline {C}$ in the following reactions ?

asked Oct 16, 2013 by meena.p

1 answer

Which one of the following is most effective in causing the coagulation of an $As_2S_3$ sol?

asked Oct 16, 2013 by meena.p

1 answer

Calculate $\Delta H^{\circ}$ for the reaction: $Na_2O+SO_3 \longrightarrow Na_2SO_4$ given the following :

asked Oct 16, 2013 by meena.p

1 answer

$20\; ml$ of $0.1\;M$ acetic acid is mixed with $50\;ml$ of Potassium acetate. $K_a$ of Acetic acid = $1.8 \times 10^{-5}$ at $27^{\circ}C$. The concentration of Potassium acetate if pH of the mixture is $4.8$:

asked Oct 16, 2013 by meena.p

1 answer

The concentration of an organic compound in chloroform is $6.15$g per $100\;mL$ of solution. A portion of this solution in a $5\;cm$ polarimeter tube causes an observed rotation of $-1.2^{\circ}.$ What is the specific rotation of the compound ?

asked Oct 16, 2013 by meena.p

1 answer

For the first order reaction at $27^{\circ}C, $ the radio of time required for $75 \%$ completion to $25 \%$ completion of reaction is :

asked Oct 16, 2013 by meena.p

1 answer

The equilibrium constant for the given reaction is 100 $N_2 +2O_2 \rightleftharpoons 2NO_2$ What is the equilibrium for the reaction given below : $NO_2 \rightleftharpoons \large\frac{1}{2}$$ N_2+O_2$

asked Oct 16, 2013 by meena.p

1 answer

The Cubic Unit cell of a metal (molar mass $=63.55\;g\;mol^{-1})$ has an edge length of $362\;pm$. Its density is $8.92\;g.cm^{-3}$. The type of unit cell is :

asked Oct 15, 2013 by meena.p

1 answer

At $25^{\circ}$ the molar conductances at infinite dilution for the strong electrolytes $NaOH,NaCl$ and $Bacl_2$ are $248 \times 10^{-4},126 \times 10^{-4}$ and $280 \times 10^{-4}s.m^2. mol^{-1}$ respectively . $\lambda^{\circ}_mBa(OH)_2$ in $s.m^2 mol^{-1}$:

asked Oct 15, 2013 by meena.p

1 answer

The synthesis of crotonaldehyde from acetaldehyde is an example of .................. reaction.

asked Oct 15, 2013 by meena.p

1 answer

For the following cell reaction $Ag | Ag^{+} | AgCl | Cl^{\ominus } | Cl_2,Pt\; \Delta G^{\circ}_f (AgCl)=-109\; kJ/mol;$$\Delta G^{\circ}_f (Cl^{\ominus})=-129 \; kJ/mol;\Delta G^{\circ}_f (Ag^+)=78\; kJ/mol ; E^{\circ}$ of the cell is :

asked Oct 15, 2013 by meena.p

1 answer

Consider the following reaction

asked Oct 15, 2013 by meena.p

1 answer

During the depression of freezing point experiment an equilibrium is established between the molecules of :

asked Oct 15, 2013 by meena.p

1 answer

Parkinson's disease is linked to abnormalities in the level of dopamine in the body. The structure of dopamine is :

asked Oct 15, 2013 by meena.p

1 answer

A codon has a sequence of $\underline {\underline {A}}$, and specifies a particular $\underline {\underline {B}}$ that is to be incorporated into a $\underline {C}$. What are $\underline {A},\underline {B},\underline {C}?$

asked Oct 15, 2013 by meena.p

1 answer

How many tripeptides can be prepared by linking the amino acids glycine, alanine and phenyl alanine?

asked Oct 15, 2013 by meena.p

1 answer

What are $\underline {X}$ and $\underline {Y}$ in the following reaction sequence :$C_2H_5OH \longrightarrow \underline{X} \longrightarrow \underline{Y}$

asked Oct 15, 2013 by meena.p

1 answer

IUPAC name of

asked Oct 15, 2013 by thanvigandhi_1

1 answer

Which one of the following order is correct for the first ionisation energies of the elements?

asked Oct 15, 2013 by meena.p

0 answers

Match the following :

asked Oct 15, 2013 by meena.p

1 answer

pH of a buffer solution decreases by $0.02$ units when $0.12 $ g of acetic acid is added to $250\;ml$ of a buffer solution of acetic acid and Potassium acetate at $27^{\circ}$. The buffer capacity of the solution is :

asked Oct 15, 2013 by meena.p

1 answer

How many 'ml' of perhydrol is required to produce sufficient oxygen which can be used to completely convert 2 lit of $SO_2$ gas to $SO_3$ gas?

asked Oct 15, 2013 by meena.p

1 answer

The correct Fischer projection formula of (2R, 3R)-2, 3-dihydroxy butanoic acid is

asked Oct 15, 2013 by thanvigandhi_1

1 answer

Assertion (A) : K,Rb and Cs form superoxides. Reason (R): The stability of the superoxides increase from 'K' to 'Cs' due to decrease in lattice energy.

asked Oct 15, 2013 by meena.p

0 answers

The average kinetic energy of one molecule of an ideal gas at $27^{\circ}C$ and 1 atm. pressure is :

asked Oct 15, 2013 by meena.p

1 answer

Aluminium reacts with $NaOH$ and forms compound 'X'.If the coordination number of aluminium in $'X'$ is 6, the correct formula of X:

asked Oct 15, 2013 by meena.p

1 answer

$1.5\;g$ of $CdCl_2$ was found to contain $0.9\;g$ of Cd. Calculate the Atomic weight of $Cd.$

asked Oct 15, 2013 by meena.p

1 answer

$SiCl_4$ on hydrolysis forms $'X'$ and HCl. Compound $'X'$ loses water at $1000^{\circ}$ and gives $'Y'$. Compounds $'X'$ and $'Y'$ respectively are :

asked Oct 15, 2013 by meena.p

1 answer

Dipole moment of $HCL=1.03\;D,HI=0.38\;D$. Bond length of $HCL=1.3\; A$ and $HI=1.6 A$. The ratio of fraction of an electric charge, $\delta$, existing on each atom in HCl and HI is :

asked Oct 15, 2013 by meena.p

1 answer

Which one of the following reactions is not correct?

asked Oct 15, 2013 by thanvigandhi_1

0 answers

Which pair of oxyacids of phosphorous contains $'P-H'$ bonds ?

asked Oct 15, 2013 by meena.p

1 answer

In Gattermann reaction, a diazonium group is replaced by $\underline {X}$ using $\underline{Y},X,Y$ are :

asked Oct 15, 2013 by meena.p

1 answer

The type of bonds present in sulphuric anhydride :

asked Oct 15, 2013 by meena.p

1 answer