To determine whether the same finishing point is obtained on testing the filtered portions in the test tubes with baric chloride as is obtained on testing with sulphuric acid, a titration was made with 20 c.c. of standard solution of sulphuric acid, together with the usual quantities of sodic acetate and acetic acid; and two lots of 2 c.c. each were filtered into two sets of test tubes after each addition of the standard baric chloride. To one series 3 drops of baric chloride solution were added, and to the other 3 drops of sulphuric acid. The results were—
| "Baric Chloride" added. | With Dilute Sulphuric Acid. | With Baric Chloride Solution. |
| 19.5 c.c. | Clear | Cloudy |
| 19.75 " | Clear | Cloudy |
| 20.0 " | Finished | Finished |
| 20.25 " | Cloudy | Clear |
| 20.5 " | Cloudy | Clear |
The two methods of testing give the same result. But this balance is disturbed in the presence of much nitre, the indications with baric chloride being disturbed by an opalescence for some c.c. beyond the finishing point. In solutions containing free hydrochloric or nitric acid, a precipitate is obtained with either baric chloride or sulphuric acid.
Effect of Varying Sulphur.—In these and the subsequent experiments the titrations were performed in the presence of 10 grams of sodic acetate and 10 c.c. of acetic acid in the manner already described.
| Standard sulphuric acid used | 5.0 c.c. | 10.0 c.c. | 20.0 c.c. | 50.0 c.c. | 100.0 c.c. |
| "Baric chloride" required | 5.0 " | 10.0 " | 20.0 " | 50.0 " | 100.0 " |
Effect of Varying Temperature.—With 5 c.c. of standard sulphuric acid titrated at 15° C., 5 c.c. of baric chloride were required; but with larger quantities the results were altogether unsatisfactory when titrated cold.
Effect of Varying Bulk.—
| Bulk | 100.0 c.c. | 200.0 c.c. | 500.0 c.c. | 1000.0 c.c. |
| "Baric chloride" required | 20.0 " | 20.0 " | 20.0 " | 20.5 " |
Considerable variation in bulk has no effect, but 500 c.c. is the most convenient volume to work with. It is well to occasionally replace the water boiled off during titration.
Effect of Foreign Salts.—In all these experiments 20 c.c. of "sulphuric acid" were used, and the titration was performed in the ordinary way.