Consider 010 M solutions of the following substances HCN C6H

Consider 0.10 M solutions of the following substances: HCN, C6HSNH2, Ca(CIO)2, HNO3, Ba(OH)2, CaCl2, CH3CH2NH3 Rank the solutions in order of increasing pH where 1 is the solution with the lowest pH and 7 is the solution with the highest pH. Which solution is ranked 2nd? HCN C6H5NH2 HNO3 Ca(CIO)2 Cacl2

Solution

Answer:

1)

HNO3 is the strongest acid present with PKa=2.4*10

HCN is the answer to this as it is a moderate Acid with pka value=4*10^-10

Cacl2-it is a salt so the ph is around seven

C6H5NH2 is analogous to NH3 (one H has been replaced by a benzene ring). It should behave like NH3 and be a weak base

Ba(oh)2-it is also a salt of the strong base , so it is highly basic

Ca(clo)2- this is also have a ph value of 6-8

Answer 2

since a buffer is also a weak base and its conjugate acid

NH3 is weak base here

adding HCl will make the following reaction

NH3 + H+ = NH4+
NH4+ is the conjugate acid of NH3 so we get
(NH3/NH4+:) this is a buffer

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