Recent questions tagged class12

The EMF of cell is : $Pt/H_2/CH_3COOH(0.1M)\parallel NH_4OH(0.01M)/H_2/Pt$.$K_a$ for $CH_3COOH=1.8\times 10^{-5}$ and $K_b$ for $NH_4OH=1.8\times 10^{-5}$

asked Feb 17, 2014 by sreemathi.v

1 answer

In which of the following crystals alternate tetrahedral voids are occupied

asked Feb 17, 2014 by sharmaaparna1

1 answer

In a solid AB having the NaCl structure A atoms occupy the corners of the cubic unit cell . If all the faces centred atoms along one of the axis are removed then the resultant stoichiometry of the solid is

asked Feb 17, 2014 by sharmaaparna1

2 answers

EMF of following cell is 0.67V at 298K $Pt/H_2(1atm)/H^+(pH=X)\parallel KCl(1N)/Hg_2Cl_2(s)/Hg$.Calculate pH of anode compartment.Given : $E^0_{Cl^-/Hg^2Cl_2/Hg}=0.28V$.

asked Feb 17, 2014 by sreemathi.v

1 answer

The co-ordination number of metal crystallizing in a structure adopting hexagonal close packing is

asked Feb 17, 2014 by sharmaaparna1

1 answer

Percentage of free space in cubic close packed structure and in body centered packed structure are respectively:

asked Feb 17, 2014 by sharmaaparna1

1 answer

By how much is oxidizing power of $MnO_4^-/Mn^{+2}$ couple decreases if the $H^+$ concentration is decreased from 1M to $10^{-4}$M at $25^{\large\circ}C$ .Assume other species have no change in concentration.

asked Feb 17, 2014 by sreemathi.v

1 answer

A small ball of mass m and charge +q tied with a string of length l , rotating in a vertical circle under gravity and a uniform horizontal electric field E as shown . The tension in the string will be minimum for

asked Feb 17, 2014 by yamini.v

1 answer

The edge length of a face centered cubic cell of an ionic substance is 508 pm .If the radius of the carbon is 110pm , the radius of the anion is

asked Feb 17, 2014 by sharmaaparna1

1 answer

Copper Crystallizes in f.c.c with a unit cell length of 361 pm. What is the radius of copper atom?

asked Feb 17, 2014 by sharmaaparna1

1 answer

The EMF of cell $Ag/AgCl(K_{sp})(saturated\; sol)\parallel Cl^-(C_1)/AgCl(K_{sp}/Ag)$ is given by

asked Feb 17, 2014 by sreemathi.v

1 answer

In a compound atoms of element Y form ccp lattice and those of element X occupy ${\large\frac{2}{3}}^{rd}$ of tetrahedral voids. The formula of the compound will be

asked Feb 17, 2014 by sharmaaparna1

1 answer

How many Faradays are required to reduce on mole of $MnO_4^-$ to $Mn^{+2}$

asked Feb 17, 2014 by sreemathi.v

1 answer

Total Volume of atoms present in a face centered cubic unit cell of a metal is (r is atomic radius)

asked Feb 17, 2014 by sharmaaparna1

1 answer

The $E_{cell}$ in which the reaction :$MnO_4^-+Fe^{+2}+H^+\rightarrow Mn^{+2}+Fe^{+3}+H_2O$ occurs is 0.59V at $25^{\large\circ}C$.The equilibrium constant for the reaction is

asked Feb 17, 2014 by sreemathi.v

1 answer

An ionic compound has unit cell consisting of A ions at the corners of a cube and B ions on the centres of the faces of cube. The empirical formula of this compound is

asked Feb 17, 2014 by sharmaaparna1

1 answer

$Zn/Zn^{+2}(C_1)\parallel Zn^{+2}(C_2)/Zn$.For this cell $\Delta G$ is -ve if

asked Feb 17, 2014 by sreemathi.v

1 answer

How many unit cells are present in a cubic shaped ideal crystals of NaCl of mass 1.0g?

asked Feb 17, 2014 by sharmaaparna1

1 answer

Na and Mg crystallise in b.c.c and f.c.c type crystals respectively , then the number of atoms of Na and Mg present in the unit cell of their respectively crystal is

asked Feb 17, 2014 by sharmaaparna1

1 answer

Which of the following facts is not true?

asked Feb 17, 2014 by sreemathi.v

1 answer

If $E^0_{Fe^{+2}/Fe}$ is $X_1$,$E^0_{Fe^{+3}/Fe}$ is $X_2$ then $E^0_{Fe^{+3}/Fe^{+2}}$ will be

asked Feb 17, 2014 by sreemathi.v

1 answer

A solution containing one mole per litre each of $Cu(NO_3)_2,AgNO_3,Hg_2(NO_3)_2,Mg(NO_3)_2$ is being electrolysed by using inert electrodes.The values of standard potentials are $E^0_{Ag^+/Ag}=0.8V$,$E^0_{Hg^{+2}/Hg}=0.79V$,$E^0_{Cu^{+2}/Cu}=0.34V$,$E^0_{Mg^{+2}/Mg}=-2.3V$ with increasing voltage the sequence of deposition of metals on the cathode will be

asked Feb 17, 2014 by sreemathi.v

1 answer

A current of 2A when passed for five hour through a molten metal salt,it deposits 22.2g of metal of atomic weight 177.The oxidation state of metal in metal salt is

asked Feb 17, 2014 by sreemathi.v

1 answer

The standard reduction potentials at 298K for following half reaction are given against each.
$Zn^{+2}(aq)+2e^-\leftrightharpoons 2n(s)=-0.762$
$Cr^{+3}(aq)+3e^-\leftrightharpoons Cr(s)=-0.740$
$2H^+(aq)+3e^-\leftrightharpoons H_2(g)=0$
$Fe^{+3}(aq)+e^-\leftrightharpoons Fe^{+2}(aq)=0.770$.

Which is the strongest reducing agent ?

asked Feb 17, 2014 by sreemathi.v

1 answer

Four moles of electrons were transferred from anode to cathode in an experiment of electrolysis of water.The total volume of two gases produced will be approximately(in litre) at STP.

asked Feb 17, 2014 by sreemathi.v

1 answer

Depression in freezing points of $0.1\;M$ aqueous solution of $HCl,CuSO_4$ and $K_2SO_4$ are

asked Feb 17, 2014 by sreemathi.v

1 answer

At 298K temperature ,the Henry constants for $Ar,CO_2,CH_4$ and $O_2$ are 40 kbar,1.6 kbar,0.41 kbar and 34 kbar respectively.Which of the following show maximum solubility in water at a given pressure?

asked Feb 17, 2014 by sreemathi.v

1 answer

Which one of the following aqueous solutions has the lowest vapour pressure?

asked Feb 17, 2014 by sreemathi.v

1 answer