Answer:
KCN forms a basic solution (option B)
Explanation:
Step 1: Data given
Acids have form AH, with conjugate base A-.
Bases have the form BOH, with conjugate acid B+.
Strong acids have weak conjugate bases
Strong bases have weak conjugate acids
Weak acids have strong conjugate bases
Weak base have strong conjugate acids
a) NaCl.
Na+ is a conjugate acid of NaOH, what is a strong base.
Cl- is the conjugate base of HCl, what is a strong acid.
They form a neutral solution
b) KCN.
K+ is a conjugate acid of KOH, what is a strong base.
CN- is the conjugate base of HCN, what is a weak acid.
K+ is a weak conjugate acid, CN- is a stronger conjugate base
They form a basic solution
c) NaNO3.
Na+ is a conjugate acid of NaOH, what is a strong base.
NO3- is the conjugate base of HNO3 , what is a strong acid.
They will form a neutral solution
d) NH4NO3.
NH4+ (ammonium) is the conjugate acid of NH3, what is a moderately strong base.
NO3- is the conjugate base of HNO3, what is a strong acid.
Ammonium is a stronger conjugate acid, nitrate is a weak conjugate base.
The solution is acid.
e) FeCl3 is an acid salt because Fe(OH)3 is weak base and HCl is a strong acid. pH is less than 7.
Fe^3+ is the conjugate acid of Fe(OH)3, what is weak base.
Cl- is the conjugate base of HCl, what is a strong acid.
Fe^3+ is a 'stronger' conjugate acid, Cl- is a weaker conjugate base.
They solution is acid