Question

Question:

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

(i) increase ist 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).

1. pH 7 means that the solution is neutral so adding a base will increase the pH
2. Adding acid will decrese the pH.

(b). Red litmus paper turns blue under basic or alkaline conditions
That is PH greater than 7

(c). The pH of solution which liberate CO2 from Na2CO3 should be less than 7 as acid can do this.