Select the pKa value of the strongest acid from the following
1.0
3.0
2.0
4.5
A.
1.0
The acid is called strong acid when it ionise upto great extent i.e. if its Ka value is large.
We know that, pKa = log
Hence, larger the value of Ka, smaller will be the value of pKa. Hence, low value of pKa means that acid is strong.
The compounds A and B are mixed in equimolar proportion to form the products, A +B C+ D. At equilibrium, one third of A and B are consumed. The equilibrium constant for the reaction is
0.5
4.0
2.5
0.25
If, in the reaction N2O4 2NO2 ,x is that part of N2O4 which dissociates, then the number of molecules at equilibrium will be
1
3
(1 + x)
(1 + x)2
For the reaction
N2 (g) + O2 (g) 2NO (g), the value of Kc at 800°C is 0.1. When the equilibrium concentration of both the reactants is 0.5 mol, what is the value of Kp at the same temperature?
0.5
0.1
0.01
0.025
A buffer solution has equal volumes of 0.2 M NH4OH and 0.02 M NH4Cl. The pKb of the base is 5. The pH is
10
9
4
7
A precipitate of AgCl is formed when equal volumes of the following are mixed [Ksp for AgCl = 10-10]
10-4 M AgNO3 and 10-7 M HCl
10-5 M AgNO3 and 10-6 M HCl
10-5 M AgNO3 and 10-4 M HCl
10-6 M AgNO3 and 10-6 M HCl
4 moles each of SO2 and O2 gases are allowed to react to form SO3, in a closed vessel. At equilibrium 25% of O2 is used up. The total number of moles of all the gases at equilibrium is :
6.5
7.0
8.0
2.0
Solubility product of a salt AB is 1 x 10-8 M2 in a solution in which the concentration of A+ ions is 10M.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