Solved Exercise, Chem-12, Ch-15


Q.01: Fill in the blanks:

(i) Fertilizers enhance the natural___________ of the soil. (fertility)

(ii) Micro-nutrients are required in quantity ranging from ________ per acre. (6—200 g)

(iii) Ammonia contains ________ % nitrogen. (82%)

(iv) Manure is an ________ material used to fertilize land. (organic)

(v) Cement was first introduced by an English mason _________. (Joseph Aspdin)

(vi) Phosphorus is required to stimulate ________ of plant. (growth)

(vii) In Pakistan, bleaching of pulp is carried out with ________. (chlorine or sodium hypochlorite and hydrogen peroxide)

(viii) Cement is generally manufactured using ________ process. (wet)

(ix) The use of cement in the construction of building is based on its property of _________ when its paste with water is allowed to stand for sometimes. (setting)

(x) Lignin is an ________ polymer and causes paper to become brittle. (aromatic)

Q.02: Indicate True or False:

(i) Potassium fertilizers are especially used for tobacco and corn. (TRUE)

(ii) Ammonia is used in gaseous state while all other fertilizers are used in the solid form. (FALSE)

CORRECT: Ammonia is used in liquid state while all other fertilizers are used in the solid form.

(iii) In wet process for the manufacture of cement, grinding of raw material is done in the presence of water. (TRUE)

(iv) The total production of cement in Pakistan is 56,30,100 metric tons/annum. (FALSE)

CORRECT: The total production of cement in Pakistan is 9,578,802 metric tons/annum.

(v) In neutral sulphite semi-chemical process, sodium sulphite is used buffered with sodium carbonate. (TRUE)

(vi) Lignin is an inorganic binder. (FALSE)

CORRECT: Lignin is an aromatic binder.

(vii) Paper consumption in Pakistan is around 5kg per person per year. (TRUE)

(viii) Urea contains 90% nitrogen. (FALSE)

CORRECT: Urea contains 46% nitrogen.

(ix) The temperature of the digester in paper industry should be around 160-180°C. (TRUE)

(x) Potassium fertilizers increase the capability of plants to resist diseases. (TRUE)

Q.03: Multiple choice questions.

(i) Which three elements are needed for the healthy growth of plants?  

(a)  N, S, P

(b)  N, Ca, P

(c)  N, P, K

(d)  N, K, C

EXPLANATION: Nitrogen, Phosphorus and Potassium are main macronutrients which are required for the healthy growth of plants.

(ii) Which woody raw material is used for the manufacture of paper pulp?

(a)  Cotton

(b)  Bagasse

(c)  Poplar

(d) Rice straw

EXPLANATION: Poplar is the woody raw material required for the manufacture of paper pulp. All other options contain non-woody raw materials, though they are also used in paper pulp.

(iii) The nitrogen present in some fertilizers helps plants:

(a)  To fight against diseases

(b)  To produce fat

(c)  To undergo photosynthesis

(d)  To produce protein

EXPLANATION: Nitrogen is the main constituent of proteins because every protein is made up of amino acids, and amino acids contain nitrogen in the form of amino groups.

(iv) Phosphorus helps in the growth of:

(a)  Root

(b)  Leave

(c)  Stem

(d)  Seed

EXPLANATION: Phosphorus is essential for energy transfer, nucleic acid synthesis, and phospholipid formation, all of which are critical processes supporting the growth and development of seeds in plants.

(v) Micro-nutrients are required in quantity ranging from:

(a)  4—40 g

(b)  6—200 g            

(c)  6—200 kg

(d)  4—40 kg

EXPLANATION: Micronutrients are the nutrients which are required by plants in very small amounts i.e., 6—200 g per acre.

(vi) During the manufacturing process of cement, the temperature of the decomposition zone goes up to:

(a)  600oC                  

(b)  900oC                  

(c)  1000oC                

(d)  1200oC

EXPLANATION: In decomposition zone which is a moderate temperature zone, lime stone (CaCO3) decomposes into lime (CaO) and CO2 at 900oC.

(vii) The word paper is derived from the name of which reedy plant:

(a)  Rose

(b)  Sun flower

(c)  Papyrus

(d) Water Hyacinth

EXPLANATION: The word paper is derived from the name of a reedy plant Papyrus, which grew abundantly along the marshy delta of the River Nile in Egypt around 3000 B.C.

(viii) Which is not a calcareous material?

(a)  Lime

(b)  Clay

(c)  Marble

(d) Marine shell

EXPLANATION: Clay is an argillaceous material, containing aluminium and silicon oxides. All others are calcareous materials containing calcium.

(ix) How many zones through which the charge passes in a rotary kiln?                         

(a)  4

(b)  3

(c)  2

(d)  5

EXPLANATION: Rotary kiln has four temperature zones through which the charge passes: (1) Drying or Pre-heating Zone (Minimum temperature zone) (2) Decomposition Zone (Moderate temperature zone) (3) Burning Zone (Maximum temperature zone) (4) Cooling Zone

(x) Ammonium nitrate fertilizer is not used for which crop?

(a)  Cotton

(b)  Wheat

(c)  Sugar cane

(d) Paddy rice

EXPLANATION: Ammonium nitrate is not suitable for paddy rice because the microbial bacteria in flooded fields decomposes it to nitrogen gas.

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