Group O of elements are unreactive because
- A. their outmost shells contain equal number of electrons
- B. their highest occupied enegy level is full
- C. they are monatomic gases
- D. they are non-metals
The electronic configuration of an element is 1\(s^2\) 2\(s^2\) 2\(p^6\) 3\(s^2\) 3\(p^3\). Where is the element located in the periodic table?
- A. Group lll, period 3
- B. Group lll, period 5
- C. Group V, period 3
- D. Group V, period 5
Which of the following statements about soapless detergents is correct? They
- A. lather readily with hard water
- B. increase the surface tension of water
- C. cause hydrolysis of salts in water
- D. from a curdy precipitate with soft water
The following compounds are hydrocarbons except
- A. methylpropanoate
- B. 2-methylbutane
- C. benzene
- D. cyclohexane
When alkynes are hydrogenated completely, they produce compounds with the general molecular formula
- A. C nH n
- B. C nH 2n+2
- C. CnH 2n
- D. CnH2n-2
Which of the following compounds can be represented by the molecular formula C2H6O?
- A. Propanel
- B. Ethanol
- C. Methanoic acid
- D. Glucose
Which of the following processes takes place during the production of margarine from vegetable oils?
- A. Esterification
- B. Hydrolysis
- C. Hydrogenation
- D. Saponification
When concentrated sodium chloride solution is electrolysed using inert electrodes the products are?
- A. oxygen and hydrogen
- B. hydrogen and oxygen
- C. sodium and oxygen
- D. soduim hydroxide, hydrogen and chlorine
If two metallic ions of the same concentration migrate to a graphite cathode, the one that would be preferentially discharged is the one that has the
- A. smaller mass
- B. lower electrical charge
- C. greater stability in solution
- D. stronger tendency to accept electrons
Which of the following ions require the largest quantity of electricity for discharge at an electrode?
- A. 2.0 mole of Q 3+
- B. 2.5 mole of R2+
- C. 4.0 mole of Y-
- D. 3.0 mole of T-
Consider the following equation; Cr2O7(aq)2- + 14H+(aq) + 6e– → 2Cr3+(aq) + 7H2O(I). The oxidation number of chromium changes from
- A. -2 to + 3
- B. - 2 to + 6
- C. + 6 to + 3
- D. + 7 to + 6
A visible change is observed when a strip of iron is placed in an aqueous solution of
- A. FeSO4
- B. ZnSO4
- C. CuSO4
- D. MgSO4
Which of the compounds will leave a metal residue when heated?
- A. Cu(NO 3 )2
- B. AgNO3
- C. K2CO3
- D. CaCO3
CuSO4 5H2O can be obtained from an aqueous solution of copper (ll) tetraoxosulphate (VI) by
- A. evaporation to dryness
- B. using chromatography
- C. precipitation
- D. crystallization
Equal amounts of marble chips are reacted separately with 100cm3 of hydrochloric acid of different concentrations . if all the marble chips reacted, which of the following remained the same in each case?
- A. Average rate of evolution of gas
- B. Total mass of gas evolved during the reaction
- C. Time taken for the reaction to reach completion
- D. lnitial reaction rates
What will happen if more heat is applied to the following system at equilibrium? X2(g) + 3Y 2(g) ⇌ 2XY3(g); ∆H =-kJmol -1
- A. the yield of XY 3 will decompose
- B. more of XY3 will decompose
- C. More of X2 will react
- D. the forward reaction will go to completion
Which of the following salt solutions will have a pH greater than 7?
- A. NaCl(aq)
- B. Na2CO3(aq)
- C. Na2SO4(aq)
- D. NaHSO4(aq)
Calculate the mass of sodium hydroxide in 5.00 dm3 of a 0.125 mol dm-3 solution [NaOH = 40 g mol]
- A. 0.0156 g
- B. 0.625 g
- C. 1.00 g
- D. 25. 0 g
Which of the following substances increases in mass when heated in air?
- A. Sodium chloride
- B. lodine crystals
- C. magnesium ribbon
- D. copper (ll) oxide
A substance is said to be hygroscopic if it absorbs?
- A. water from the atmosphere to form a solution
- B. heat from the surrounding
- C. carbon (IV) oxide from the atmosphere
- D. moisture from the atmosphere without dissolving
Which of the following acids forms normal salts only?
- A. Tetraoxosulphate (VI) acid
- B. Trioxosulphate (IV) acid
- C. Tetraoxophosphate (V) acid
- D. Trioxonitrate (V) acid