Question

(a) A solution has a Ph of 7. Explain how you would: (i) increase its Ph;

(ii) decrease its pH.

(b) If a solution changes the colour of litmus from red to blue, what can you say about its Ph?

(c) What can you say about the Ph of a solution that liberates carbon dioxide from sodium carbonate?

Answer 1

(a)(i) The pH increases by the addition of base.

(ii) The pH decreases by the addition of acid.

(b) If the solution changes the colour of litmus from red to blue, the pH indicates the presence of base.

(c) The solution that liberates carbon dioxide from sodium carbonate has pH less than 7.