MCQOPTIONS
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| 1. |
Which of the mentioned gas is used as protective atmosphere to prevent oxidation in metalworking and food preservation? |
| A. | N<sub>2</sub> |
| B. | O<sub>2</sub> |
| C. | H<sub>2</sub> |
| D. | CO<sub>2</sub> |
| Answer» B. O<sub>2</sub> | |