Question

1. List five questions about the rate at which Alka-Seltzer^® tablets dissolve if the temperature was held constant and one of the controlled variables was changed. Develop a new hypothesis based on one of the questions. Remember that a hypothesis must be testable with empirical or measurable data.

Answer 1

The questions framed are as follows:

1. Does the rate of dissolution depend on the form in which tablets are added? State the relationship between them considering a situation where intact tablets are added versus where the same number of tablets in powdered form is added keeping the rest of the parameters constant.

2. How does the change in nature of solvent affect the rate of dissolution of the tablet? Hint: Let one of the solvent is non-polar like benzene while the other is polar like water.

3. How does the rate of tablet dissolution depend on the following parameters : a. Number of tablets added? b. Amount of solvent taken. If yes, elaborate observation and also specify theoretical reason, if any.

4. Suppose there are three beakers, each of them containing same number of tablets in equal volume of same solvent. One is kept still on a table, the other is kept on a rotary shaker and the third one is kept over a magnetic stirrer. All the apparatus kept in the same room. State if there will be any difference in the time taken for dissolution. If yes, explain the reason behind.

5. Does the rate of tablet dissociation depend on pH. If yes, mention how is it affected by acidic, basic and neutral solvents?

Any of the above question can be taken as hypothesis. Let us take the 2nd question here.

Hypothesis: The dissolution of Alka-Seltzer tablets depends on the nature of the solvents taken.

Way to prove the hypothesis:

- 2 beakers are taken containing equal volume of benzene and water respectively.

- 2 tablets are added to each of the beakers at the same time.

- 2 separate stopwatches can be used to monitor the final time when the dissolution of the tablets in each of them gets completed.

- Care should be taken such that the remaining conditions remain unaltered.

- Readings are taken to determine the rate of dissolution of tablets in the two solvents.