Passage II
An acid-base titration involves slowly adding a measured amount of acid to a solution containing a base and an indicator. The indicator, a dye, signals the endpoint (exact point where the acid has consumed all of the base) by changing colors as the solution goes from basic to acidic. The pH scale is a relative measure of the strength of acids and bases (see Figure 1). Table 1 shows the amount of acid required to reach the endpoint of different basic solutions containing various natural indicators.
Figure adapted from J. Dudley Herron et al., Heath Chemistry. ©1987 by D.C. Heath and Company.
8. Which of the following statements about the pH of the basic solutions before and after the titration is consistent with the data in Table 1 ?
Your Answer is
Correct Answer is G
Explanation
Looking at table 1, before titration, the initial pH is greater than 7, which is alkaline;
After titration, the final pH is less than 7, which is acidic. The pH becomes lower, so the titrant is an acid