a. A solution has a pH of 7 (seven). Explain how you would

i. increase its pH


ii. decease its pH


(b) What can you say about the pH of a solution that liberate CO2 from sodium carbonate? Write the balanced chemical equation for the reaction.

(a) The pH of seven indicates that the given solution is neutral in nature.

(i) In order to increase the pH of the solution that is to make the solution more alkaline, one needs to add base to the solution.


(ii) In the similar manner to decrease the pH which means the solution should become more acidic, one needs to add an acid to the given


(b) The pH of the solution which can liberate CO2 from sodium carbonate has to be less than seven because sodium carbonate is a basic salt and an acidic solution can only liberate the CO2 from it. The reaction is as follows:


Na2CO3 + 2HCl → 2NaCl + H2O + CO2


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