Final answer:
A substance called a leak detection solution or soapy water solution is used to test welding equipment connectors for gas leaks. Applying this solution to the connectors will produce bubbles if there is a leak.
Step-by-step explanation:
When testing welding equipment connectors for gas leaks, you generally use a substance called a leak detection solution or a soapy water solution. This solution is a mixture of water and a small amount of liquid soap or detergent. By applying this solution to the connectors, any gas leaks will produce small bubbles. These bubbles indicate the presence of a leak in the welding equipment connectors.