Which of the following molecules acts as a Lewis acid ?
(CH3)3B
(CH3)2O
(CH3)3P
(CH3)3N
The Strongest conjugate base is______________
NO3-
Cl-
SO4 2-
CH3COO-
The compound whose aqueous solution has the highest pH is______________
NaCl
NaHCO3
Na2CO3
NH4 Cl
Which one of the following is most soluble ?
Bi2S3(KSP=1×10-70)
MnS(KSP=7×10-16)
CuS(KSP=8×10-37)
Ag2S(KSP=6×10-51)
The hydride ion H- is strong base than its hydroxide ion OH-. Which one of the following reactions will occur if sodium hydride (NaH) is dissolved in Water ?
2H-(aq) + H2O(l)→H2O+H2 +2e-
H-(aq) + H2O(l)→OH-+H2
H - + H2O(l) → no reaction
None of the above
Which one of the following substance will have 0.1M solution of basic?
Sodium borate
Calcium nitrate
NH4Cl
Sodium sulphate
The solubility of a saturated solution of calcium fluoride is 2×10-4 mol / L . Its solubility product is_____________
12×10-2
14×10-4
22×10-11
32×10-12
Which of the following statements about pH and H+ ion concentration is incorrect ?
addition of one drop of concentrated HCl in NH4OH solution decreases pH of the solution.
A solution of the mixture of one equivalent of each CH3COOH and NaOH has a pH of 7 .
pH of pure neutral water is not zero .
A cold and con.H2SO4 has lower H+ ion concentration than a diluted solution of H2SO4
A Physician wishes to prepare a buffer solution at pH =3.58 that efficiently resist changes in pH yet contains only small concentration of the buffering agents. Which one of the following weak acid together with its sodium salt would be best to use ?
m-chlorobenzoic acid (pKa=3.98)
P-Chlorocinnamic acid(pKa = 4.41)
2,5 -dihydroxy benzoic acid (pKa=2.97)
Acetoacetic acid(pKa=3.58)
Calculate the pOH of a solution at 250C that contains 1.0×10-6 M of hydronium ions .
7.00
4.00
9.00
1.00
