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Which of these is least likely to act as a Lewis base?
(c) Electron rich species are called Lewis base. Among the given, BF3 is an electron deficient species, so have a capacity of electron accepting instead of donating that's why it is least likely act as a Lewis base. It is a Lewis acid.
Equimolar solutions of the following substances were prepared separately. Which one of these will record the highest pH value?
(a) BaCl2 is a salt of strong acid HCl and strong base Ba(OH)2. So, its aqueous solution is neutral with pH 7. All other salts give acidic solution due to cationic hydrolysis, so their pH is less than 7. Thus, pH value is highest for the solution of BaCl2
Which of the following is least likely to behave as Lewis base?
(b) BF3 is an electron deficient species, thus behaves like a Lewis acid.
A buffer solution is prepared in which the concentration of NH3 is 0.30 M and the concentration of is 0.20 M. If the equilibrium constant, Kb for NH3 equals 1.8 x 10-5, what is the pH of the solution?
(log 2.7 = 0.43)
pOH = pKb + log[salt]/[Base]
= -log Kb + log [salt]/[base]
= -log 1.8 x 10-5 + log(0.20/0.30)
= 5-0.25 +(-0.176)
= 4.75-0.176 = 4.57
... pH = 14-4.57
The value of H for the reaction
X2(g) + 4Y2(g) 2XY4(g) is less than zero.
Formation of XY4(g) will be favored at
X2(g) + 4Y2 2XY4(g);
H<0 and n<0
... The forward reaction is favored at high pressure and low temperature. (According to Le-Chatelier's principle)
For the reaction N2(g) + O2(g) 2NO(g) the equilibrium constant is K1. The equilibrium constant is K2 for the reaction 2NO(g) + O2(g) 2NO2(g). What is K for the reaction NO2(g) + 1/2N2(g)+ O2(g)?
N2(g) + O2(g) 2NO(g);K1 ..... (i)
2NO(g) + O2(g) 2NO2(g);K2 .... (ii)
N2(g) + 2O2(g) 2NO2(g);K=K1xK2
For NO2(g) 1/2N2(g) + O2(g);
K= [1/K1K2]1/2
What is [H+] in mol/L of a solution that is 0.20 M in CH3COONa and 0.10 M in CH3COOH? (Ka for CH3COOH = 1.8 x 10-5)
Key Idea CH3COOH (weak acid) and CH3COONa (conjugated salt) form acidic buffer and for acidic buffer,
pH = pKa + log[salt]/[acid]
and [H+] = -antilog pH
pH = -logKa + log[salt]/[acid] [... pKa = -logKa]
= -log(1.8 x 10-5) + log(0.20)/(0.10)
= 4.74 + log2
= 4.74 + 0.3010 = 5.041
Now, [H+] = antilog(-5.045)
= 9.0 x 10-6 mol/L
In which of the following equilibrium Kc and Kp are not equal?
Key Idea The reaction for which the number of moles of gaseous products (np) is not equal to the number of moles of gaseous reactants (ng) has a different value of Kc and Kp.
(a) np = nR = 2, thus, Kp = Kc
(b) np = nR = 2, thus, Kp = Kc
(c) nP =nR =2, thus, Kp =Kc
(d) nP=2, nR=1, thus, Kp Kc
Which one of the following molecular hydrides acts as a Lewis acid?
(c) Key Idea Electron deficient molecules behave as Lewis acid. Among the given molecules, only diborane is electron deficient, ie, does not have complete octet. Thus, it acts as a Lewis acid. NH3 and H2O being electron rich molecules behave as Lewis base.
Which of the following molecules acts as a Lewis acid ?
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