Two substances are allotropes of carbon if

  1. Both reduce heated iron (II) oxide to iron
  2. Have different crystalline structure
  3. Have equal masses
  4. Have equal shape
  5. Have the same arrangement of atoms
Choose Answer :


  Which of these can be reduced when heated with carbon?

  1.  Aluminium  
  2. Calcium carbonate
  3. Iron (III) oxide 
  4. Magnesium oxide 
  5.  Sodium oxide.
Choose Answer :


Which of the following sets of elements is arranged in order of increasing electronegativity?

  1.  Chlorine, fluorine, nitrogen, oxygen, carbon
  2.  Fluorine, chlorine, oxygen, nitrogen, carbon
  3.  Carbon, nitrogen, oxygen, chlorine, fluorine 
  4. Nitrogen, oxygen, carbon, fluorine, chlorine
  5.  Fluorine, nitrogen, oxygen, chlorine, carbon.
Choose Answer :


Which of the following pair of gas can be prepared in the laboratory and collected over water?

  1. Oxygen and Ammonia
  2. Hydrogen and Hydrochloric acid
  3. Hydrogen and Ammonia
  4. Oxygen and Hydrogen chloride
Choose Answer :


 Which among the following equations correctly shows the reaction between chlorine gas and water?

  1. Cl 2(g) + H 2 O (l) ? Cl 2(g)
  2. 2Cl 2(g) + 2H 2 O (l) ? 4Cl + O 2(g) + 2H 2(g)
  3. Cl 2(g) + H 2 O (l) ? HCl (aq) + HOCL (aq)
  4. 2Cl 2(g) + 2H 2 O (l) ? 2HOCl 2(aq) + H 2(aq)
  5. 2Cl 2(g) + 3H 2 O (l) ? Cl 2(g) + 2H 3 O + .
Choose Answer :


Which among the following pair of substances are allotropes?

  1. H 2 O and H 2 O 2
  2. 12 C and 14 C
  3. P 4 and P 8
  4. H 2 and 2H +
  5. H + and H 3 O.
Choose Answer :


In the following equilibrium equation, 2S02(g) +O2(g)  2S03 The forward reaction is exothermic. Which change would increase the production of sulphur trioxide at equilibrium?

  1.  Increasing temperature
  2.  Decreasing temperature
  3.  Decreasing sulphur trioxide concentration 
  4. Decreasing pressure 
  5. Adding a catalyst.
Choose Answer :


The ionic equation when aqueous ammonium chloride reacts with sodium hydroxide solution is represented as:

  1. 2NH+4(aq) + 2Cl-(aq)à 2NH3(g) + Cl2(g) + H2(g)
  2. NH+4(aq) + OH-(aq) à NH3(g) + H2O(l)
  3. Na+(aq) + Cl-(aq) à NaCl(g)
  4. H+(aq) + OH-(aq) à H2O(l)
  5. 2NH+4(aq) + 2Cl-(aq) à 2NH3(g) + 2HCl(g).
Choose Answer :


 Substance X liberates chlorine gas from acidified potassium chloride. The behaviour of X is described as:

  1.  an oxidising agent    
  2.  an oxidising and reducing agent
  3.  catalyst   
  4.  a reducing agent
  5.  bleaching agent.
Choose Answer :


  In the industrial preparation of sulphur trioxide, equilibrium is established between sulphur dioxide and oxygen gas as follows:

 Is the forward reaction an endothermic or exothermic process? Give a reason.

View Ans


How would you adjust temperature and pressure to maximize the proportion of the product at equilibrium?

View Ans


Why is it unfavorable to work with very high pressure and very low temperature in the Contact process?

View Ans


What catalyst is used to speed up the rate of formation of sulphur trioxide before attaining the equilibrium?

View Ans


Explain each of the following statements and in each give its balanced chemical equation: 

  1.  Sulphur dioxide in solution is a powerful reducing agent.
  2. Sulphur dioxide in solution act as a bleaching agent.
  3. Sulphur dioxide can reduce chlorine and itself become oxidized.
  4. When hydrogen sulphide is passed through sulphur dioxide gas, yellow deposits are produced. (7 marks)
View Ans


Match the items in List A with the responses in List B by writing the letter of the correct response beside the item number in the answer booklet provided.Match the items in List A with the responses in List B by writing the letter of the correct

List A List B
  1. An element which is extracted by Frash process.
  2. A gas with pungent choking smell and forms misty.
  3. A substance used for sterilization of drinking water.
  4. An alkaline gas.
  5. A compound used in domestic water - softening.
  6. A compound prepared by fermentation of carbohydrates.
  7. The compounds with a general formula of C„ H2„+1 COOH.
  8. The hardest allotrope of carbon.
  9. A gas which turns lime-water milky.
  10. A substance which is amorphous form of carbon.
  1. Carbon dioxide
  2. Carboxylic acids
  3. Iron (III) oxide
  4. Nitrogen
  5. Diamond
  6. Sodium carbonate
  7. Hydrogen chloride
  8. Sulphur
  9. Graphite
  10. Ethanol
  11. Chlorine
  12. Calcium
  13. Ammonia gas
  14. Plastic sulphur
  15. Coke
View Ans


 The following flow diagram shows the stages in the contact process

 (i)     Give the names of element A, catalyst B and an acid C.

 (ii)  Write  a balanced chemical equation for the formation of sulphur trioxide in stage 2

View Ans


  (i) Name the products formed when hydrogen sulphide react with chlorine gas.

(ii) Mention two uses of hydrochloric acid.

View Ans


  Three moles of nitrogen gas combine with five moles of hydrogen gas to form ammonium gas by Haber process.

  1.  Which reactant is present in smaller amount?
  2.  Calculate the grams of the reactant left in the container.
  3.  How many moles of NH3 are produced?
  4.  How many litres of NH3 are produced at STP?
View Ans


 Write balanced chemical equations to show how chlorine reacts with the following:

  1. water.
  2. aqueous iron (II) chloride solution.
  3. hydrogen sulphide.
View Ans


  The preparation of ammonia in the laboratory is done by heating any ammonium salt with an alkali.

(i)  Write a balanced chemical equation for the preparation of ammonia gas.

(ii)  State two uses of ammonia.

View Ans


(i) Explain why sulphur and its compounds are removed from fuels before they are burned.

(ii) Describe how sulphur dioxide is changed into sulphur trioxide. Give the reaction conditions and the equation(s)

View Ans



  (i) Write the reaction equations involved in the industrial manufacturing of sulphuric acid starting with sulphur dioxide in the contact process.

 (ii) Explain why sulphur trioxide is not dissolved directly in water to obtain sulphuric acid in contact process.

View Ans


(a) For each of the following reactions, identify which of the gases, chlorine, sulphur dioxide, and hydrogen sulphide is either an oxidizing agent or reducing agent. Explain how you arrived at your answers.

(i)  Cl2(g) + 2H2O(l) + SO2(g) ? 2HCl(g) + H2SO4(aq).

(ii)  SO2(g) + 2H2S(g) ? 2H2O(l) + 3S(s)

View Ans


 The formation of oxides of non-metals can be both beneficial and harmful to man. Justify the statement focusing on the oxides of carbon, nitrogen and sulphur.

View Ans


 Match the items in List A with the responses in List B by writing the letter of the correct response beside the item number in the answer booklet provided.

  1. Its hydride is the only alkaline gas.
  2. Possesses 11 electrons.
  3. Most electronegative element.
  4. Extracted by Frasch process.
  5. A noble gas.
  6. Exists in oxidation state of +3 in haematite.
  7. Least reactive metal in the reactivity series of metals. 
  8. A non metal which is a good conductor of heat and electricity.
  9. Vital for all living things
  10. Its oxide is yellow when hot and white when cold.

  1. Sodium
  2. Aluminum
  3. Iron
  4. Gold
  5. Oxygen
  6. Flourine
  7. Sulphur
  8. Argon
  9. Ozone
  10. Iodine
  11. Mercury
  12. Chlorine
  13. Magnesium
  14. Calcium
  15. Nitrogen
  16. Carbon
  17. Lithium
  18. Potassium
  19. Hydrogen
  20. Zinc 
View Ans


 (a) With the help of chemical equation, what will be observed when ammonia reacts with

(i) Hydrogen chloride.

(ii) Copper (II) oxide.

(b) It is not advisable to sleep inside a house which is not well ventilated with a burning wooden charcoal. Give a reason for that and write the chemical equation to represent your answer.

View Ans


The chemical properties of concentrated sulphuric acid can be grouped into oxidizing property and dehydrating property. In which property should sulphuric acid be grouped when it reacts with copper metal? Give reason and write the equation of the reaction.

View Ans


Match the items in LIST A with the responses in LIST B by writing the letter of the correct response beside the item number.



(i) Oxygen

(ii) Sulphur dioxide

(iii) Ammonia

(iv) Hydrogen Chloride

(v) Carbon monoxide

(vi) Nitrogen

(vii) Hydrogen

(viii) Chlorine

(ix) Nitrogen dioxide

(x) Carbon dioxide

  1. Green­yellow gas which rapidly bleaches damp litmus paper
  2.  Heats with cracking sound
  3.  It rekindles a glowing splint of wood
  4.  Colourless gas, extremely poisonous since it combines with hemoglobin in red blood cells.
  5.  Brown­ring test
  6.  Produces a white precipitates of silver chloride in a drop of a solution of silver nitrate
  7.  It is the only alkaline gas
  8.  Substitution reaction
  9.  Explodes with air when flame applied
  10.  Sweet ­ aroma smell
  11.  It is a brown gas
  12.  It is very irritating smell and decolorizes potassium manganate (VII) solution with no precipitation left
  13.  It turns lime water milky
  14.  Colourless, odourless, non­poisonous gas commonly used as a refrigerant
  15.  Characteristic yellow flame
  16.  Good solvent for fats and grease, non­poisonous
  17.  Blackens lead (II) ethanoate paper
  18.  Turns brown on exposure to air
  19.  Freezes at 0°C and boils at 100°C
  20.  Rotten­ egg smell
View Ans


Ammonia is very soluble in water and less dense than air. How does each of the properties determine the way in which ammonia is collected in a gas jar? (4 marks)

View Ans


Give reasons for the following:

(i) Solution of chlorine in water is acidic

(ii) Yellow phosphorus is stored under water.

View Ans

Download Learning
Hub App

For Call,Sms&WhatsApp: 255769929722 / 255754805256

Bofya Hapa Kupakua
App Ya Learning Hub Tanzania