21. | Phosphorus vapour comprises of |
a. | P |
b. | P₂ |
c. | P₃ |
d. | P₄ |
View Answer Report Discuss 50-50! |
Answer: (d).P₄
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22. | Conversion of yellow phosphorous to red phosphorous is done by heating it in covered retorts at __________ °C in absence of air. |
a. | 50-80 |
b. | 250-400 |
c. | 1000-1200 |
d. | 800-900 |
View Answer Report Discuss 50-50! |
Answer: (b).250-400
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23. | Commercial fertilisers are available mostly in the form of |
a. | powder |
b. | grannules |
c. | lumps |
d. | flakes |
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Answer: (b).grannules
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24. | Pick out the wrong statement. |
a. | All the nitrogenous fertilisers are not soluble in water. |
b. | A straight fertiliser contains only one nutrient. |
c. | Calcium cynamide is used as weed killer in onion fields. |
d. | The phosphorous nutrient makes the plant stem stronger and increases its branches. |
View Answer Report Discuss 50-50! |
Answer: (a).All the nitrogenous fertilisers are not soluble in water.
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25. | Ammonia synthesis gas is produced from natural gas by |
a. | thermal cracking |
b. | steam reforming |
c. | partial oxidation |
d. | hydrogenation |
View Answer Report Discuss 50-50! |
Answer: (b).steam reforming
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