The function of sulphur during vulcanization rubber is to?
- A. act as catalyst for the polymerization of rubber molecules
- B. convert rubber from thermosetting to thermo plastics polymer
- C. from chains which bind rubber molecules together
- D. break down rubber polyer
- E. shorten the chain length of rubber polyer
Which of the following roles does sodium chloride play in soap preparation? It
- A. reacts with glycerol
- B. purifies the soap
- C. accelerates the decomposition of the fat or oil
- D. separates the soap from the glycerol
- E. converts the fatty acid to its sodium salt
An aqueous solution of an inorganic salt gave white precipitate (i) soluble in excess aqueous NaOH (ii) insoluble in excess aqueous NH3 (iii) with dilute HCl. The cation present in the inorganic salt is?
- A. Na4+
- B. Ca++
- C. Zn++
- D. Al+++
- E. Pb++
The process involved in the conversion of an oil into margarine is known as?
- A. hydrogenation
- B. condensation
- C. pyrolysis
- D. dehydration
- E. cracking
Addition of dilute hydrochloride acid to an aqueous solution of a crystalline salt yield a yellow precipitate and a gas which turned dichromate paper green. The crystalline salt was probably?
- A. Na2SO4
- B. Na2S
- C. Na2S2O3.5H2O
- D. Na2CO3
- E. NaHCO3
When marble is heated to about 1473 K, another white solid is obtained which reacts vigorously with water to give an alkaline solution. The solution contains?
- A. NaOH
- B. KOH
- C. Mg(OH)2
- D. Zn(OH)2
- E. Ca(OH)2
The atomic number of an element whose cation, X2+, has the ground state electronic configuration 1s22s22p63s22p6 is?
- A. 16
- B. 18
- C. 20
- D. 22
- E. 24
Which of the following compounds is NOT the correct product formed when the parent metals is heated in air?
- A. Calcium oxide (CaO)
- B. Sodium oxide (Na2O)
- C. Copper (ll) oxide (CuO)
- D. Tri-iron tetroxide (Fe3O4)
- E. Aluminium oxide (Al2O3)
A colourless organic compound X was burnt in excess air to give two colourless and odourless gases, Y and Z, as products. X does not decolorize blue bromine vapour, Y turns lime milky while Z gives a blue colour with copper (ll) tetraoxosulphate (IV).
Y and Z are respectively?
- A. CO2 and NH3
- B. CO and NH3
- C. SO2 and H2O
- D. CO2 and H2O
- E. SO2 and NH3
A colourless organic compound X was burnt in excess air to give two colourless and odourless gases, Y and Z, as products. X does not decolorize blue bromine vapour, Y turns lime milky while Z gives a blue colour with copper (ll) tetraoxosulphate (IV).
Compound X is?
- A. an alkene
- B. an alkane
- C. an alkyne
- D. tetrachloromethane
- E. dichloromethane
Which of the following substances is the most abundant in the universe?
- A. Carbon
- B. Air
- C. Water
- D. Oxygen
- E. Hydrogen
Solid sodium hydroxide on exposure to air absorbs a gas and ultimately gives another alkaline substance with the molecular formula?
- A. NaOH.H2O
- B. NaOH.N2
- C. Na2CO3O
- D. NaHCO3
- E. NaNO3O
An organic compound decolourized acidified KMnO4 solution but failed to react with ammoniacal silver nitrate solution. The organic compound is likely to be?
- A. a carbonxylic acid
- B. an alkane
- C. an alkene
- D. an alkyne
- E. an akanone
Tetraoxosulphate (IV) ions are finally tested using?
- A. acidified silver nitrate
- B. acidified barium chloride
- C. ime-water
- D. dilute hydrochloric acid
- E. acidified lead nitrate
The energy change (ฮH) for the reaction CO(g) + (1)/(2)O2(g) โ is?
(ฮHi(CO) = -110.4 kJ mol–) (ฮHi(CO2) = -393 kJ mol–)
- A. -503.7 kJ
- B. +503.7kJ
- C. -282.9 kJ
- D. +282.9 kJ
- E. +393.3 kJ
When pollen grains are suspended in water and viewed through a microscope, they appear to be in a state of constant but erratic motion. This is due to?
- A. convection currents
- B. small changes
- C. small changes in temperature
- D. a chemical reaction between the pollen grain and water
- E. the bombardment of the pollen grains by molecules of water
A man suspected of being drunk is made to pass his breath into acidified potassium dichlormate solution. If his breath carries a significant level of ethanol, the final colour of the solution is?
- A. pink
- B. purple
- C. orange
- D. blue-black
- E. green
Which of the following is used in the manufacture of bleaching powder?
- A. Sulphur dioxide
- B. Chlorine
- C. Hydrogen tetraoxosulphate (VI)
- D. Hydrogen sulphide
- E. Nitrogen dioxide
Complete hydrogenation of ethyne yields?
- A. benzene
- B. methane
- C. ethane
- D. ethene
- E. propane
In the reaction H2(g)O \(\to\) H2(g) + 1/2O2(g)
ฮH = -2436000 KJ, which of the following has no effect on the equilibrium position?
- A. Adding argon to the system
- B. Lowering the temperature
- C. Adding hydrogen to the system
- D. Decreasing the pressure
- E. Increasing the temperature
Which of the following metals will displace iron from a solution of iron(ll)tetraoxosulphate(lV)?
- A. Copper
- B. Mercury
- C. Silver
- D. Zinc
- E. Gold