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Thank you!
Soln 1)
we know that for an acid base reaction
A- + H2O <-------------------------------------> HA + OH-
where , A- = base
HA = conjugate acid
now
i) conjugate acid of ClO- = HClO
Kb of ClO- = 3.3 x 10^-7
we know that
Kb x Ka = 10^-14
=> Ka for HClO = 3.03 x 10^-8
ii) conjugate acid of CO3^2- = HCO3-
Kb of CO3^2- = 1.8 x 10^-4
we know that
Kb x Ka = 10^-14
=> Ka for HCO3- = 5.56 x 10^-11
iii) conjugate acid of HS- = H2S
Kb of HS- = 1.8 x 10^-7
we know that
Kb x Ka = 10^-14
=> Ka for H2S = 5.56 x 10^-8
iv) conjugate acid of NH2CH3 = NH3^+CH3
Kb of NH2CH3 = 4.4 x 10^-4
we know that
Kb x Ka = 10^-14
=> Ka for NH3^+CH3 = 2.27 x 10^-11
we know that ,
A large Ka value indicates that a strong acid because it means the acid is largely dissociated into its ions and hence formation of product is more favoured
therefore , H2S is the strongest acid among them with the highest Ka value
Soln )
1) pH = 3.0
we know that , pH + pOH = 14
=> pOH = 11
also, pOH = - log[OH-]
=> [OH-] = 10^-pOH
= 1 x 10^-11
b) conc of HNO3 = 10^-4
HNO3 <-----------------------> H+ + NO3^-
=> [H+] = 10^-4
we know that
[H+] x [OH-] = 10^-14
=> [OH-] = 10^-10
c) given
pOH = 12
we know that
pOH = - log[OH-]
=> [OH-] = 10^-pOH
= 10^-12
d) we know that pOH of pure water = 7
=> [OH-] of pure water = 10^-7
e) GIVEN
conc of NH4Cl = 10^-3
NH4Cl <-----------------------> NH4^+ + Cl-
NH4^+ + H2O <---------------------> NH3 + H+
=>[H+] = [NH4Cl]
=>[H+] = 10^-3
we know that
[H+] x [OH-] = 10^-14
=> [OH-] = 10^-11
OPTION C has the lowest [OH-]
Hey guys, I am having a lot of trouble with my homework. Could you please help?...
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