The octane number of a fuel whose performance is the same as that of a mixture of 55 g of 2,2,4- trimethly pentane and 45 g of n-heptane is ?
- A. 45
- B. 55
- C. 80
- D. 100
Alkaonic acids have low volatility compared with alkanols because they?
- A. are more polar than alkaonls
- B. have two oxygen atoms while alkanols have one
- C. form hydrogen bonds while alkanols do not
- D. form two hydrogen bonds while alkanols form one
The label on a reagent bottle containing a clear organic liquid dropped off.The liquid was neutral to litmus and gave a colourless gas with metallic sodium. The liquid must be an?
- A. alkanoate
- B. alkaene
- C. alkanol
- D. alkane
A cycloalkane with the molecular formula C5H10 has ?
- A. one isomer
- B. two isomers
- C. three isomers
- D. four isomers
Which of the following compounds gives a yellow residue when heated and also reacts with aqueous sodium hydroxide to give a white gelatinous precipitate soluble in excess sodium hydroxide solution?
- A. (NH4)CO3
- B. ZnCO3
- C. Al2(SO4)3
- D. PbCO3
To make coloured glasses, small quantities of oxides of metals which form coloured silicates are often added to the reaction mixture consisting of Na2CO3 and SiO2. Such a metals is a?.
- A. pottasium
- B. barium
- C. zinc
- D. copper
Sodium hydroxide should be stored in properly closed containers because it?
- A. readily asborbs water vapour to air
- B. is easily oxidize by atmospheric oxygen
- C. turns golden yellow when exposed to light
- D. melts at a low temperature
The major component of the slag from the production of iron is?
- A. an alloy of calcium and iron
- B. coke
- C. impure iron
- D. calcium trioxosilicate (IV)
Coal fire should not be used in poorly ventilated rooms because ?
- A. of the accumulation of CO2 which causes dep sleep
- B. it is usually too hot
- C. of the acumulation of CO which causes suffocation
- D. it removes most most of the gases in the rooms
Which of the following metals will liberate hydrogen from steam or dilute acid?
- A. Copper
- B. Iron
- C. Lead
- D. Mercury
A metallic oxide which reacts with both HCl and NaOH to give salt and water only can be classified as?
- A. an acidic oxide
- B. a basic oxide
- C. a neutral oxide
- D. an amphoteric oxide
In the Haber process for the manufacture of ammonia, the catalyst commonly used is finely divided ?
- A. vanadium
- B. platinum
- C. iron
- D. copper
Which of the following tests will completely identify anyone of surphur (VI) oxide, hydrogen, carbon (IV) oxide and nitrogen (II) oxide?
- A. Pass each gas into water and test with blue litmus paper
- B. Pass each gas into lime water
- C. Expose each gas to atmospheric air
- D. Pass each gas to concentrated tetraoxosulphate (IV) acid
The brown fumes given off when trioxonitrate (V) acid is heated consist of ?
- A. NO2 and O2
- B. H2O and NO2
- C. NO2' O2 and H2O
- D. NO, NO2 and H2O
Which of the following gases can be collected by the upward displacement of air?
- A. NO
- B. H 2
- C. NH3
- D. Cl 2
In the reaction:
2Hl(g) ↔ H2(g) + l2(g)’ ΔH = 10 kj;
The concentration of iodine in the equilibrium mixture can be increased by?
- A. raising the pressure
- B. raising the temperature
- C. adding a catalyst
- D. lowering the pressure
Which of the following samples will react fastest with dilute trioxonitrate (V) acid?
- A. 5 g of lumps of CacO3 at 25°C
- B. 5 g of powered CacO3 at 25°
- C. 5 g of lumps of CaCO3 at 50°C
- D. 5 g of powered CaCO3 AT 50°C
Iron galvanized with zinc is cathodically protected from corrosion. This is because?
- A. zinc has a more positive oxidation potential than iron
- B. zinc has less positive oxidation potential than iron
- C. bith have the same oxidation potential
- D. zinc is harder than iron
Fe\(_2\)O\(_{3(s)}\) + 2Al\(_{(s)}\) → Al\(_2\)O\(_3\) + 2Fe\(_{(s)}\). If the heats of formation of Al\(_2\)O\(_3\) and Fe\(_2\)O\(_3\) are – 1670 kJmol\(^{-1}\) and – 822 kJmol\(^{-1}\) respectively, the enthalpy change in kJ for the reaction is ?
- A. +2492
- B. +848
- C. -848
- D. -2492
In the reaction 1O–3 + 5l– + 6H+ → 312 + 3H2O, the oxidizing agent is?
- A. H+
- B. l-
- C. 1O-
- D. l2
Cr2O7 + 6Fe2+ + 14H+ → 2Cr3+ +6Fe3+ + 7H2O. In the above , the oxidation number of chromium changed from?
- A. +7 to +3
- B. +6 to +3
- C. +5 to +3
- D. -2 to +3