Final answer:
In the context of the described experiment, sodium carbonate is typically used as the primary standard due to its suitability for precise and accurate measurements in acid-base titration. Option c is correct.
Step-by-step explanation:
The primary standard used in the experiment described can be identified by looking at the chemicals involved and their role in the typical procedures of a titration experiment. In the context of acid-base titrations and the provided information, sodium carbonate (Na2CO3) is often used as a primary standard because it is pure, stable, non-hygroscopic, and has a high molar mass, making it easy to weigh accurately.
Other substances mentioned, such as hydrochloric acid (HCl) and boric acid (B(OH)3), are not typically used as primary standards due to their volatility or other properties. Though sodium tetraborate (Na2B4O7) can also serve as a primary standard, in the context of neutralization reactions, sodium carbonate is more commonly used.