Which of the following is an example of a non-corrosive flux?

Rosin paste is considered a non-corrosive flux because it is typically derived from natural resin and does not contain aggressive chemicals that can corrode metal surfaces during soldering or welding processes. Its primary function is to help clean the metal surfaces and facilitate the flow of solder by preventing oxidation without causing damage to the workpieces.

In contrast, other options such as muriatic acid, zinc chloride, and hydrochloric acid are classified as corrosive fluxes. These substances contain strong acids or reactive compounds that can lead to oxidation or corrosion of metal surfaces, potentially causing damage and reducing the integrity of the joint. Therefore, rosin paste stands out as a safe choice for applications where non-corrosive behavior is essential.