| # | Polyphosphates may be used in water treatment to | retard corrosion and adjust pH. | retard corrosion and reduce taste and odors. | retard corrosion and calcium scale. | retard corrosion and reduce chlorine demand. | none of the above | 3
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| 1 | Corrosive waters can be a result of the presence of | calcium | acids | magnesium | organic material | bases | 2 |
| 2 | The possible corrosive action of a filtered water on metals can be detected by the | determination of total chlorine. | orthotolidine test. | oxygen-consumed test. | Langelier Index. | none of the above. | 4 |
| 3 | A substance added to water to promote the formation of a protective film in transmission pipes is known as | a passivator. | an inhibitor. | cathodic protection. | a pacifier. | none of the above | 2 |
| 4 | What metallic element should be monitored for when using caustic soda for corrosion control? | xinc | copper | iron | sodium | carbon | 4
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