chemistry MCQs - 12th class Chapter 15 Mcqs

1

Which three elements are considered the most important nutrients essential for plant growth?

A

Nitrogen, Sulphur, Potassium

B

Nitrogen, Phosphorus, Potassium

C

Calcium, Magnesium, Sulphur

D

Carbon, Hydrogen, Oxygen

2

Micronutrients are generally required in quantities ranging from __________ per acre.

A

5 kg to 200 kg

B

1 kg to 5 kg

C

6 grams to 200 grams

D

200 grams to 500 grams

3

Urea is a high-quality nitrogenous fertilizer containing about ______ nitrogen.

A

82%

B

33.5%

C

75%

D

46%

4

In the manufacture of urea, gaseous carbon dioxide is mixed with ammonia in a volume ratio of:

A

1:1

B

2:1

C

1:3

D

1:2

5

The process of solidifying molten urea into droplets is called:

A

Condensation

B

Prilling

C

Evaporation

D

Decomposition

6

Ammonium nitrate contains approximately ______ nitrogen.

A

33-33.5%

B

46%

C

16%

D

82%

7

Which fertilizer is not suitable for paddy rice due to decomposition by microbial bacteria?

A

Urea

B

Potassium Nitrate

C

Ammonium Nitrate

D

Diammonium Phosphate

8

Diammonium phosphate contains 16% nitrogen and ______ P2O5.

A

13%

B

44%

C

48%

D

75%

9

Potassium is required for the formation of ______ in plants.

A

Proteins

B

Starch, sugar, and fibrous material

C

Fats

D

Oils

10

Potassium nitrate (KNO3) is prepared by the double decomposition reaction between sodium nitrate and:

A

Potassium Sulphate

B

Potassium Carbonate

C

Potassium Hydroxide

D

Potassium Chloride

11

Who first introduced the building material known as cement in 1824?

A

Ts'ai Lun

B

Joseph Aspdin

C

Alfred Nobel

D

Dmitri Mendeleev

12

What is the percentage of Lime (CaO) in a good sample of Portland cement?

A

22%

B

7.5%

C

62%

D

2.5%

13

In the wet process of cement manufacturing, what is the proportion of limestone and clay in the slurry?

A

50% limestone, 50% clay

B

75% limestone, 25% clay

C

25% limestone, 75% clay

D

60% limestone, 40% clay

14

The rotary kiln for cement manufacturing is typically how long?

A

10-20 feet

B

50-100 feet

C

100-200 feet

D

300-500 feet

15

At what temperature does limestone decompose into lime (CaO) and CO2 in the rotary kiln?

A

500°C

B

1500°C

C

900°C

D

200°C

16

The burning zone in a rotary kiln reaches a temperature up to:

A

900°C

B

1200°C

C

1500°C

D

2000°C

17

The final product obtained from the rotary kiln before grinding is known as:

A

Slurry

B

Clinker

C

Gypsum

D

Cement powder

18

What percentage of gypsum is ground with clinkers to produce finished cement?

A

10%

B

5%

C

2.0%

D

15%

19

The setting of cement involves a reaction with:

A

Acid

B

Oil

C

Air

D

Water

20

The word 'paper' is derived from the name of a reedy plant called:

A

Mulberry

B

Bamboo

C

Papyrus

D

Eucalyptus

21

The invention of modern paper in 105 A.D. is credited to:

A

An Egyptian scholar

B

A Roman engineer

C

Ts'ai Lun of China

D

Joseph Aspdin of England

22

Which of the following is a woody raw material used for paper production?

A

Bagasse

B

Wheat straw

C

Poplar

D

Cotton linter

23

Which of the following is a non-woody raw material for paper production?

A

Eucalyptus

B

Douglas fir

C

Rice straw

D

Poplar

24

Which process is most commonly used in the pulp and paper industry in Pakistan?

A

Kraft process

B

Sulphite process

C

Neutral sulphite semi-chemical process

D

Mechanical pulping

25

The digester in the paper pulping process is maintained at a temperature of:

A

100-120°C

B

160-180°C

C

200-220°C

D

80-100°C

26

What is the main purpose of the digestion process in paper making?

A

To bleach the pulp

B

To remove soluble lignin

C

To dry the paper

D

To press the fibres

27

The colour of pulps obtained from chemical pulping is mainly due to:

A

Cellulose

B

Water content

C

Residual lignin

D

Added chemicals

28

Which chemical is commonly used as a bleaching agent in the Pakistan paper industry?

A

Sulphuric acid

B

Sodium hydroxide

C

Chlorine

D

Ammonia

29

* "The final moisture content of dried paper wound on a reel is about:"

A

1-2%

B

15-20%

C

25-30%

D

6-8%

30

Paper consumption in Pakistan is around ______ per person per year.

A

1 kg

B

10 kg

C

25 kg

D

5 kg

31

Macronutrients are generally required in quantities ranging from ______ per acre.

A

6 g to 200 g

B

5 kg to 200 kg

C

1 kg to 2 kg

D

250 kg to 500 kg

32

An understanding of the function of plant nutrients was the first prerequisite for the use of:

A

Pesticides

B

Herbicides

C

Fertilizers

D

Manure

33

Which element imparts a green colour to the leaves and enhances the yield of plants?

A

Phosphorus

B

Potassium

C

Nitrogen

D

Calcium

34

Liquid ammonia as a fertilizer contains ______ nitrogen.

A

46%

B

33%

C

13%

D

82%

35

The reaction to produce Diammonium Phosphate is an _________ reaction.

A

Endothermic

B

Exothermic

C

Neutralization

D

Decomposition

36

Which material provides acidic components like aluminates and silicates for cement?

A

Calcareous material

B

Gypsum

C

Argillaceous material

D

Water

37

In Pakistan, most cement factories use the _______ for production.

A

Dry process

B

Wet process

C

Semi-dry process

D

Direct process

38

The slurry prepared for cement manufacturing contains about ______ water.

A

5-10%

B

10-20%

C

35-45%

D

60-70%

39

How many zones does the charge pass through in a rotary kiln?

A

2

B

3

C

5

D

4

40

The setting of cement in the first 24 hours involves the formation of a colloidal gel of hydrated...

A

Tricalcium silicate

B

Calcium hydroxide

C

Tricalcium aluminate

D

Aluminium hydroxide

41

Paper is defined as a sheet material made up of a network of natural ______ fibres.

A

Protein

B

Polyester

C

Nylon

D

Cellulosic

42

In the neutral sulphite semi-chemical process, the cooking liquor is buffered to neutralize:

A

Organic acid

B

Inorganic base

C

Residual chlorine

D

Excess water

43

During pulp washing, an 80-mesh sieve is used to remove the:

A

Black liquor

B

Water

C

Uncooked materials

D

Bleaching agents

44

What is the purpose of the 'calendar stock' in a paper making machine?

A

To dry the sheet

B

To press out water

C

To reduce thickness and smooth the surface

D

To form the web

45

Phosphorus is required to stimulate early growth and accelerate ______ formation.

A

Leaf and stem

B

Root

C

Flower

D

Seed and fruit

46

In what form must nutrient elements be present in a fertilizer for the plant to absorb them?

A

Water insoluble

B

Gaseous

C

Solid rock

D

Water soluble

47

The total production of urea fertilizer in Pakistan in 2002 was about ______ metric tons/annum.

A

1,000,000

B

9,578,802

C

5,630,100

D

330,000

48

Cement clinker has the appearance of greenish black or grey coloured balls varying in size from:

A

Sand to gravel

B

Powder to dust

C

Small nuts to peas

D

Large rocks to boulders

49

The invention of modern paper involved using the bark of which tree?

A

Oak

B

Pine

C

Mulberry

D

Maple

50

In the paper making process, the 'head box' discharges a uniform jet of:

A

Water

B

Pulp suspension

C

Bleaching agent

D

Steam