Question

pH OF ACID, SALT, AND BUFFER SOLUTIONSE Name Section # PRELABORATORY ASSIGNMENT Due at the beginning of the lab period. Define (using a complete sentence). 1. Common lon Effect: Bronsted Base: 2. Calculate the pH of the following solutions (work must be shown). Include the balanced equation for the acid dissociation reaction in part (b). 0.55 M NaOH a. b. 0.10 M HOCI (K, = 3.5 X 10)

Answer 1

1) common ion effect:- presence of common ion(same type of ion) suppress the ionisation of weak acid and base.

2) Bronsted Base :- The proton accepter species are known as Bronsted base.

2) a) 0.55 M NaOH

As NaOH is strong base ,so it dissociates completely.

[NaOH ] = [OH-] = 0.55 M

pOH = -log([OH-])

= -log(0.55) => 0.26

pH = 14- pOH => pH = 14-0.26

= 13.74

b) balanced chemical reaction

HOCl + H2O <------> H3O^{​​​​+} + OCl^{​​​​-}

As it weak acid

pH= 1/2[pKa -log(C)]

= 1/2[7.46-log(0.1)]

= 4.23