Separation of mixture of solids by physical methods can be based on differences in the following except
- A. melting point
- B. solubility
- C. particle size
- D. molar mass
- E. magnetic property
The position of equilibrium in a reversible reaction is affected by
- A. particle size of the reactants
- B. change in concentration of the reactants
- C. change in size of the reaction vessel
- D. vigorous stirring of the reaction mixture
- E. presence of a catalyst
How much heat will be liberated if 8g of hydrogen burns in excess oxygen according to the following equation? 2H2 + O2→ 2H2O,∆H = -571.7KJ (H = 1)
- A. 1.42.9KJ
- B. 571.7KJ
- C. 1143.4KJ
- D. 285.9KJ
- E. 2286.8KJ
If the value of ∆H for a reaction is negative, it means that the reaction is
- A. slow
- B. exothermic
- C. spontaneous
- D. irreversible
- E. not feasible
What is the value of x in the following equation? MnO- 4 + 4H+ + xe- → MnO 2 + 2H2O
- A. 2
- B. 3
- C. 4
- D. 7
- E. 8
From the following equations, what is the order of decreasing reactivity of X, Y and Z? Y (s) + X2+(aq) → Y2+(aq) + X(s) X(s) + Z2+(aq) → X2+(aq) + Z(s)
- A. X>Y>Z
- B. Y > X > Z
- C. Z > Y > X
- D. Y > Z > X
- E. X > Z > Y
The common feature of reactions at the anode is that
- A. electrons are consumed
- B. oxidation is involved
- C. ions are reduced
- D. the electrode dissolves
- E. the electrolyte is diluted
What quantity of electrons (in mole) is lost when one mole of iron (ll) ions is oxidized to iron (lll) ions?
- A. 5 mole
- B. 4 mole
- C. 3 mole
- D. 2 mole
- E. 1 mole
Which of the following ions will migrate to the cathode during electrolysis?
- A. Zinc ions
- B. Chloride ions
- C. Sulphide ions
- D. Tetraoxosulphate (Vl) ions
- E. Trioxonitrate (V) ions
The loss of molecules of water of crystallization to the atmosphere by some crystalline salts is known as
- A. efflorescence
- B. effervescence
- C. phosphorescence
- D. fluorescence
- E. deliquescence
Which of the following is a general method of preparing acids?
- A. Direct combination of constituent elements
- B. Reaction between a base and an amphoteric oxide
- C. Double decomposition involving a salt solution
- D. Reaction between an anhydride and water
- E. Dissolution of hydroxides followed by neutralization
Which of the following is a general method of preparing acids?
- A. Direct combination of constituent elements
- B. Double decomposition involving a salt solution
- C. Reaction between an anhydride and water
- D. Reaction between a base and an amphoteric oxide
- E. Dissolution of hydroxides followed by neutralization
An acid is a substance which in the presence of water produces
- A. salts
- B. oxygen
- C. effervescence
- D. hydroxonium ions
- E. hydrogen gas
A given volume of methane diffuses in 20 seconds. How long will it take the same volume of sulphur (IV) oxide to diffuse under the same conditions? [CH4 = 16; SO2 = 64]
- A. 5 seconds
- B. 20 seconds
- C. 40 seconds
- D. 60 seconds
- E. 80 seconds
An increase in the pressure of a gas results in a decrease in its
- A. mass
- B. vapour density
- C. volume
- D. temperature
- E. concentration
If the atomic number of an element X is 11 and that of nitrogen is 7, the most likely formula of the nitride of X is
- A. X3N
- B. XN3
- C. X3N2
- D. N2X
- E. NX2
A sodium atom and a sodium ion have the same
- A. number of neutrons
- B. number of electrons
- C. electric charge
- D. electronic structure
- E. chemical properties
In linear molecules, the bond angle is
- A. 90o
- B. 140o
- C. 109o
- D. 120o
- E. 180o
What is the most probable group of an element which is a soft, silvery white solid and reacts violently with water?
- A. Group 0
- B. Group 1
- C. Group 4
- D. Group 6
- E. Group 7
Radon is used as a tracer in medical research because it
- A. is monatomic
- B. is radioactive
- C. is a noble gas
- D. has a complete valence shell
- E. has a low boiling point
How many unpaired electrons are there in an atom of an element with the following electronic configuration? 1s22s22p6
- A. o
- B. 1
- C. 2
- D. 6
- E. 8