Answer the following questions (assuming that all activity coefficients are equa
ID: 554076 • Letter: A
Question
Answer the following questions (assuming that all activity coefficients are equal to 1), including showing all working: (2a). What salt would you obtain from a neutralisation reaction between of Benzoic acid with ammonia? (1 mark) b) State whether an aqueous solution of the salt (from your answer to (a)) would be neutral, acidic or alkaline. Briefly explain your reasoning behind your answer. (3 marks) its relevance to buffer solutions. (4 marks) d)Estimate the pH of an aqueous buffer solution containing 0.237M of Benzoic acid and 0.233M of its sodium salt. (2 marks)Explanation / Answer
a)Benzoic acid+ ammonia = benzamide
C6H5COOH+ NH3 = C6H5CONH2
b) aqueous solution of benzamide is basic as there is proton acceptor which takes up H+
c)Le Chatelier's principle states that when a system experiences a disturbance (such as concentration, temperature, or pressure changes), it will respond to restore a new equilibrium state.
A buffer solution ueses Le Chatelier's principle to prevent its pH from changing very much when acid or base is added.
d)pH= pKa+ log (salt/acid)
pKa of benzoic acid = 4.2
pH= 4.2+log(0.233/0.237)
pH= 4.192