What is the number of moles of NaHCO3in 250cm3 of its solution if the solution contains 8.4 g of NaHCO3 in 1 dm3 of the solution. [Na = 23, 0 = 16, C = 12, H = 1)
- A. 1
- B. 0.25
- C. 0.05
- D. 0.025
- E. 0.01
In the reaction 2H2S(g) + SO2(g) → 2H2SO(I)+3S(s)SO2is acting as _agent
- A. a bleaching
- B. a dehydrating
- C. an oxidizing
- D. a precipitating
- E. a reducing
What is the change in the oxidation number of phosphorus in the following reaction?
4P(s) + 5O2(ag) → 2P2O5(s)
- A. 0 to 2
- B. 0 to 5
- C. 4 to 2
- D. 4 to 5
- E. 4 to 10
Chlorine displaces bromine from aqueous potassium bromide because
- A. bromine is a liquid at room temperature
- B. bromine is weakly acidic.
- C. bromine has a greater atomic radius than chlorine
- D. chlorine is a stronger oxidising agent than bromine.
- E. the density of chlorine is less than the density of bromine.
The pH of water is 7.
What is the pH of orange juice?
- A. 7
- B. above 10
- C. below 2
- D. between 5.5 and 6.5
- E. between 7.5 and 8.5
Small amounts of compounds of transition metals are sometimes added to glass during manufacture in order to make the glass
- A. acquire certain colours
- B. easier to melt
- C. easier to mould
- D. little brittle
- E. more transparent
Which separation technique is routinely applied in the petroleum industry?
- A. chromatography
- B. distillation
- C. evaporation
- D. fractional crystallization
- E. fractional distillation
Which metal is extracted from bauxite?
- A. aluminium
- B. calcium
- C. copper
- D. magnesium
- E. tin
Why is tetraoxosulphate(VI) acid NOT used for making carbon dioxide from calcium carbonate? It is
- A. a dehydrating agent
- B. a strong acid
- C. an oxidising agent
- D. dibasic
- E. forms insoluble calcium tetraoxosulphate(Vl)
Which hydrocarbon does NOT exhibit structural isomerism?
- A. C3H6
- B. C4H6
- C. C4H8
- D. C4H10
- E. C5H12
What is formed when starch is completely hydrolysed?
- A. fructose
- B. glucose
- C. lactose
- D. maltose
- E. sucrose
Ethene decolourises acidified potassium tetraoxomanganate(VII) solution. Which gas will decolourise bromine water?
- A. CH4
- B. C2H6
- C. C3H6
- D. C3H8
- E. C6H6
Which method is used for the purification of copper from its ore?
- A. distillation
- B. electrochemical
- C. electrolysis
- D. neutralization
- E. reduction
What is the concentration (in mol dm3) of a solution containing 28 g of potassium hydroxide per 100 cm3 of solution? (K=39; H=1; 0=16)
- A. 0.01
- B. 0.05
- C. 0.1
- D. 0.5
- E. 2.8
At s.t.p, a mole of chlorine occupies 22.4dm3. If the temperature is changed to 35°C and the pressure to 750mHg the of the new volume will be [Cl = 35.5]
- A. \(\frac{760\times 22.4\times 308}{750\times 273\times 35.5} dm^3 \)
- B. \(\frac{760\times 22.4\times 308}{750\times 273}dm^3 \)
- C. \(\frac{750\times 22.4\times 35.5}{760\times 273}dm^3\)
- D. \(\frac{760\times 22.4\times 35.5}{750\times 22.3\times 273}dm^3 \)
- E. \(\frac{760\times 22.4\times 35.5}{750\times 308}dm^3 \)
How many Faradays of electricity are required to liberate 9g of aluminium? [Al = 27]
- A. 0.1
- B. 0.3
- C. 1
- D. 2.7
- E. 3
Which metal bromide is widely used in photography?
- A. calcium bromide
- B. magnesium bromide
- C. potassium bromide
- D. silver bromide
- E. sodium bromide
What change will occur during the electrolysis of brine using carbon electrodes?
- A. Chlorine will be given off at the anode
- B. Oxygen gas will be given off at the anode
- C. Sodium will be deposited at the cathode
- D. The resulting solution, after electrolysis, will be acidic.
- E. The volumes of hydrogen and chlorine given off during the same time are equal
Which metal is a constituent of both bronze and solder?
- A. copper
- B. lead
- C. silver
- D. tin
- E. zinc
An atom of element X has an electronic configuration of \( 1s^22S^22p^63s^23p^3. \) In which group of the periodic table is X?
- A. \( \text{0} \)
- B. 2
- C. 3
- D. 4
- E. 5
What mass of silver is deposited when a current of 2.6 A is passed through a solution of a silver salt for 40 minutes? [Ag= 108 ; F=96500C]
- A. 6.89g
- B. 6.93g
- C. 6.98g
- D. 7.04g
- E. 7.12g