In which of the following process , maximum increase in entropy is observed ?
Melting of ice
Sublimation of naphthalene
Condensation of water
Dissolution of salt in water
The basic structural. unit and its geometry in silicates is :
SiO2 , tetrahedral
Si , square planar
SiO2 , square planar
Si , tetrahedral
Which of the following sets of quantum numbers is not possible ?
n = 4 , l =1 , m = 0 , s =
n = 4 , l = 3 , m = - 3 , s =
n = 4 , l = 1 , m = + 2 , s =
n = 4 , l = 0 , m = 0 , s =
Solubility product of a salt AB is 1 x 10-8 M in a solution in which the concentration of A+ ions is 10-3 M .The salt , will precipitate when the concentration of B- ions is kept :
between 10-8 M to 10-7 M
between 10-7 M to 10-8 M
> 10-5 M
< 10-8 M
For a reaction to be spontaneous at all temperatures ,
G and H till should be negative
G and H till should be positive
G = S = 0
H < G
For a reversible reaction ;
X (g) + 3Y (g) 2Z (g) ; H = -40 kJ , the standard entropies of X , Y and Z are 60 , 40 and 50JK mol-1 respectively .The temperature at which the above reaction attains equilibrium is about :
400 K
500 K
273K
373K
B.
500 K
X (g)+ 3Y (g) 2Z (g)
S = 2So (Z) - {So(X) + 3So (Y)}
= 2 X 50 - {60 + 3 X 40}
= 100 - 180
= - 80 JK-1 mol-1
Given , H0 = - 40 kJ
= - 40,000 J
Go = H0 - TS0
At equilibrium , G° = 0
Ho = TSo
or T =
=
= 500 K