Consider the following data on some weak acids and weak bases: Secure https//www

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Consider the following data on some weak acids and weak bases:

Secure https//www-awh.aleks.com/aleksogv/lst.exe/to u-lgNslkr78P3jH-IBxdufZeiq1apRdEMO8HO O ADVANCED MATERAL Predicting the qualitative acid-base properties of salts Consider the following data on some weak acids and weak bases: acid base name formula hydrofluoric acd HF 68 10anline CHNH, 43 x 10-10 name formula ammaniaNH 1.S 10 -5 nitrous acid HNO 45 10 Use this data to rank the following solutions in order of increasing pH. In other words, select a the solution that will have the next lowest pH, and so on. solution pH 0.1 M KF 0.1 M KNO 0.1 M NaNO 0.1 M NH4Br choosa one choose one choose one choose one Explanation Check Type here to search

Explanation / Answer

KF is a salt produces by the combination of strong base KOH and weak acid HF as follows,

KOH + HF -----> KF + H2O

so the pH of the salt is given by,

pH = 7 + 1/2(pKa + logC)

pH = 7 + 1/2(-log(6.8*10^-4) + log(0.1))

pH = 8.084

KNO3 is salt of strong base KOH and strong acid HNO3 as follows,

KOH + HNO3 -----> KNO3 + H2O

so both are strong so complete dissociation of ions and produces H2O so pH of the salt is neutral.

pH = 7

NaNO2 ia salt of the weak acid and strong base NaOH as follows,

NaOH + HNO2 -----> NaNO2 + H2O

so pH of the salt is given by,

pH = 7 + 1/2(pKa + logC)

pH = 7 + 1/2(-log(4.5*10^-4) + log(0.1))

pH = 8.173

NH4Br is salt of weak base NH3 and strong acid HBr as follows,

NH3 + HBr -----> NH4Br

so pH of the salt is given by,

pH = 7 - 1/2(pKb + logc)

pH = 7 - 1/2(-log(1.8*10^-5) + log(0.1))

pH = 5.128

Order of pH of NaNO2 > pH KF > pH of KNO3 > pH of NH4Br

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