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
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
The heat of formarion of CO2 is - 393 kJ mol-1 .The amount of heat evolved in the formation of 0.156 kg of CO2 .
- 1393 kJ
+ 1165.5 kJ
+ 1275.9 kJ
- 1165.5 kJ
In an isobaric process, when temperature changes from T1 to T2 ,S is equal to
2.303 Cp log (T2/T1)
2.303 Cp ln (T2/T1)
Cp ln (T1/T2)
Cv ln (T2/T1)
Heat of neutralisation of an acid with a base is 13. 7 kcal when :
both acid and base are weak
acid is weak and base is strong
both acid and base are strong
acid is strong and base is weak
C.
both acid and base are strong
Heat of neutralisation for strong acid and strong base is always close to 13.7 kcal .
+ H2O + AB
H = - 13.7 Kcal
The heat of neutralisation of strong acid and strong base is actually the heat of formation of 1 gmole of water from 1 g of H+ and 1 g of OH- .
Hess's law is based on :
law of conservation of mass
law of conservation of energy
enthalpy is a state function
none of the above
Assertion : A reaction which is spontaneous and accompanied by decrease of randomness must be exothermic.
Reason : All exothermic reactions are accompanied by decrease of randomness.
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 enthalpy change (H) for the neutralisation of M HCl by caustic potash in dilute solution at 298 K is :
68 kJ
65 kJ
57.3 kJ
50 kJ
Calculate change in internal energy if H = - 92.2 kJ, P = 40 atm and V = -1L.
-42 kJ
-88 kJ
+88 kJ
+42 kJ