Which of the following pairs of a chemical reaction is certain to result in a spontaneous reaction?
Endothermic and decreasing disorder
Exothermic and increasing disorder
Endothermic and increasing disorder
Exothermic and decreasing disorder
Identify the correct statement for change of Gibbs energy for a system (Gsystem) at constant temperature and pressure
If Gsystem = 0, the system has attained equilibrium
If Gsystem = 0, the system is still moving in a particular direction
If Gsystem = 0, the process is not spontaneous
If Gsystem = 0, the process is spontaneous
The standard emf of a galvanic cell involving cell reaction with n = 2 is found to be 0.295 V at 25°C. The equilibrium constant of the reaction would be
2.0 × 1011
4.0 × 1012
1.0 × 102
1.0 × 1010
nXm emit one α and two β- particles. It is converted into
nXm - 4
n - 1Xm - 1
nZm - 4
None of these
Which is the weakest acid out out of HF, HCl, HBr and HI?
HF
HCl
HBr
HI
A.
HF
The strength of an acid depends upon its degree of ionisation which in turn, depends upon the bond energy thus, higher the bond dissociation energy lower is the degree of ionisation and hence, weaker is the acid. Bond dissociation energies of the halogen acids increases in the order
HI < HBr < HCl < HF
Therefore, strength of the acid increases in the order-
HF < HCl < HBr < HI
A compound has the empirical formula CH2O. Its vapour density is 30. Its molecular formula is
C2H4O2
C2H6O
C2H6O2
C2H4O