Which of the following does not come under the category of ‘secondary nutrient’ for plant growth ?

A. Hydrogen peroxide, air and water
B. Anhydrous ammonia and air
C. Anhydrous ammonia, air and water
D. Wet ammonia, air and water

A. Ammoniacal liquor
B. K2CO3 solution
C. Dilute H2SO4
D. Dilute HCl

A. 30-35
B. 15-20
C. 65-70
D. 85-90

A. Can use only high grade phosphate rock
B. Is used less frequently
C. Produces a valuable by-product called gypsum
D. Is weak acid process

A. Exothermic
B. Endothermic
C. Non-catalytic
D. Autocatalytic

A. Phosphoric acid
B. Superphosphate
C. Phosphorous
D. Triple superphosphate