CBSE
Multiple Choice QuestionsIdentify the correct statement for the change of Gibbs energy for a system (ΔGsystem) at constant temperature and pressure
If ΔGsystem > 0, the process is spontaneous
If ΔGsystem =0, the system has attained equilibrium
If ΔGsystem < 0, the system is still moving in a particular direction
If ΔGsystem < 0, the system is still moving in a particular direction
The enthalpy and entropy change for the reaction:
Br2 (l) + Cl2 (g)→ 2BrCl (g)
are 30 kJ mol-1 and 105 JK-1 mol-1 respectively. The temperature at which the reaction will be in equilibrium is:
285.7 K
273 K
450 K
450 K
The hydrogen ion concentration of a 10-8 M HCL aqueous solution at 298 K (Kw = 10-14) is:
1.0 x 10-6
1.0525 x 10-7 M
9.525 x 10-8 M
9.525 x 10-8 M
Which of the following, not a correct statement?
The electron -deficient molecules can act as Lewis acids
The canonical structures have no real existence
Every AB5 molecules does, in fact, have square pyramid structure
Every AB5 molecules does, in fact, have square pyramid structure
For the reaction,
CH4 (g) + 2 O2 (g) ⇌ CO2 (g) + 2H2O (l),
ΔrH = - 170. 8 kJ mol-1
Which of the following statements is not true?
At equilibrium, the concentrations of CO2 (g) and H2O (l) are not equal
The equilibrium constant for the reaction is given by Kp = 
Addition of CH4 (g) or O2 (g) at equilibrium will cause a shift to the right
Addition of CH4 (g) or O2 (g) at equilibrium will cause a shift to the right
Which of the following pairs consitutes a buffer?
HNO2 and NaNO2
NaOH and NaCl
HNO3 and NH4NO3
HNO3 and NH4NO3
The most stable carbonium ion among the following is
The following equilibrium constants are given:
N2 + 3H2 ⇌ 2NH3; K1
N2 +O2 ⇌ 2NO; K2
H2 + 1/2O2 ⇌ H2O' K3
The equilibrium constants for the oxidation of NH3 by oxygen to give NO is:
K2K33 /K1
KK2K32 /K1
K22K3 /K1
K22K3 /K1
When 750 mL of 0.5 M HCl is mixed with 250 mL of 2 M NaOH solution, the value of pH will be
pH = 7
pH > 7
pH < 7
pH = 0
HgCl2 and I2 both when dissolved in water containing I– ions the pair of species formed is
HgI2 , I3-
Hgl2, I-
HgI43-, I3-
HgI43-, I3-
