The heats of combustion of carbon monoxide at constant pressure and at constant volume at 27°C will differ from one another by :
27 cal
54 cal
300 cal
600 cal
A buffer solution is prepared by mixing 0.1 M ammonia and 1.0 M ammonium chloride. At 298 K, the pKb of NH4OH is 5.0. The pH of the buffer is
10.0
9.0
6.0
8.0
The standard emf of a cell, involving one electron change is found to be 0.591 V at 25°C. The equilibrium constant of the reaction is (F = 96500 C mol-1)
1.0 × 101
1.0 × 105
1.0 × 1010
1.0 × 1030
The pH of 10-8 M NaOH aqueous solution at 25°C, is
7.02
7.0
6.89
6.0
A.
7.02
[OH-] of NaOH = 10-8M
Since, the concentration of OH- obtained from NaOH is very low, the concentration of OH- water cannot be neglected. Thus,
Total [OH-] = [OH-]NaOH + [OH-]
= 10-8 + 10-7
= 10-7 (1.1) = 1.1 × 10-7
pOH = -log[OH-]
= -log (1.1 × 10-7 ) = 6.96
pH = 14-6.69 = 7.04