pH is defined as the negative logarithm [to the base 10] of the hydrogen ion concentration expressed in moles/litre. Thus, pH = -log10H+. It represents the strength of acids and alkalis, expressed in terms of hydrogen ion concentration [H+ aq.]
(i) When, H+ ions = OH– ions, the solution is neutral with pH = 7.
(ii) When the solution evolves CO2 when heated with Na2CO3, it is acidic in nature with pH less than 7.
(iii) when, OH–ions > H+ aq. ions, the solution is basic in nature with pH more than 7.
1. Name the apparatus ‘A’. 2. Name the substance ‘X’ placed in ‘A’ and the substance ‘Y’ placed in B. 3. State the reason for conducting the titration using the apparatus ‘A’ and ‘B’. 4. State which solution is transferred to the evaporating dish and evaporated to point of crystallization for obtaining the salt. 5. State why titration is not conducted for the preparation of copper [II] sulphate crystals by neutralization.