State the colour change in a universal indicator e.g. pH paper on

(i) slightly acidic soil

(ii) slightly alkaline soil

(iii) dairy milk

(iv) human blood tested for medical diagnosis.

Define (i) salt (ii) normal salt (iii) acid salt – with relevant examples and equations.

State whether litmus is a common acid-base indicator or a universal indicator.

Define pH value. What would you say about the pH of a solution in which

(i) H⁺ aq. ions = OH^- ions

(ii) evolves CO₂ when heated with Na₂CO₃

(iii) OH^-ions > H⁺ aq. ions.