CBSE
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
In equilibrium state , the value of G is :
zero
negative
positive
may be negative or positive
pH of a 0.01 M solution (Ka = 6.6 10-4)
7.6
8
2.6
5
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
Assertion : AgCl is more soluble in NH3 than in water.
Reason : Ammonia is more polar than water.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Assertion : The equilibrium constant is fixed and a characteristic for any given chemical reaction at a specified temperature.
Reason: The composition ofthe final equilibrium mixture at a particular temperature depends upon the starting amount of reactants.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
The pH of 10-8 M HCl solution is :
8
more than 8
between 6 and 7
slightly more than 7
Which one of the following salts on being dissolved in water gives pH > 7 at 25°C ?
KCN
KNO3
NH4Cl
NH4CN
The dissociation equilibrium of a gas AB2 can be represented as
The degree of dissociation is x and is small compared to 1. The expression relating the degree of dissociation (x) with equilibrium constant KP and total pressure p is
(2Kp/p)1/2
Kp/p
2Kp/p
(2kp/p)1/3
Assertion : PCl5, is covalent in gaseous and liquid states but ionic in solid state.
Reason : PCl, in solid state consists of tetrahedral PCcation and octahedral PC anion.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.