When dilute aqueous solutions of lead (II) nitrate and potassium bromide are mixed, a precipitate is observed.
The products of this reaction are?
- A. PbO(s) + Br- + KNO3
- B. Br2 + NO2(g) + PbBr2(s)
- C. PbO(s) + K+(aq) + Br(aq) + NO2(g)
- D. PbBr2(s) + K(aq) + K+(aq) + NO3(aq)
Which of the following is a property of ionic chlorides?
- A. They can be decomposed by heat
- B. They react with aqueous AgNO3 to give a white precipiate which is soluble in excess ammonia
- C. They explode when in contact with dry ammonia
- D. They react with concentrated tetraoxosulphate (IV) acid to give white fumes of chlorine gas
An experiment produces a gaseous mixtures of carbon (IV) oxide and carbon (II) oxide. In order to obtain pure carbon (II) oxide, the gas mixture should be?
- A. passed over heated copper (II) oxide
- B. bubbled through concentrated tetraoxosulphate (IV) acid
- C. bubbled through sodium hydroxide solution
- D. bubbled through water
Which of these salts will produce its metal, oxygen and nitrogen (IV) oxide on heating?
- A. Silver and trioxonitrate (V)
- B. Sodium trioxonitrate (V)
- C. Calcium trioxonitrate (V)
- D. Lithium trioxonitrate (V)
Which of these gases can be dried with concentrated H2SO4?
- A. HBr
- B. H2S
- C. NH3
- D. SO2
NaCI(s) + H2SO4(I) → HCI(g) + NaHSO4(s).
In the reaction above, H2SO4 behaves as?
- A. a strong acid
- B. an oxidizing agent
- C. a good solvent
- D. a dehydrating agent
10g of a solid is in equilibrium with its own vapour.
When 1 g of a small amount of solid is added, the vapour pressure?
- A. remains the same
- B. drops
- C. increases by 1%
- D. increases by 99%
The standard enthalpies of formation of CO2(g), H2O(g) and CO(g) in kJ mol– are -394, -242 and -110 respectively. What is the standard enthalpy change for the reaction CO(g) + H2(g)O → CO2(g) + H2(g)?
- A. -42 KJ mol-
- B. +42 KJ mol-
- C. -262 KJ mol-
- D. +262 KJ mol-
A reaction takes places spontaneously if?
- A. ∆G = O
- B. ∆S < O and ∆H > O
- C. ∆H < T ∆S
- D. ∆G > O
The oxidation states of chlorine in HOCL, HCLO3 and HCLO4 are respectively?
- A. -1, +5, and +7
- B. -1, -5 and 7
- C. +1, +3 and +4
- D. +1, +5 and +7
Which of the reactions occurs at the anode during the electrolysis of a very dilute aqueous solution of sodium chloride?
- A. OH- - e → OH
- B. CIsup>- - e → CI
- C. OHsup>- + CIsup>-HCI + O2
- D. Na+ - esup>- Hg (Na)/(Hg) amalgam
During the electrolysis of a salt of a metal M, a current of 0.5 A flows from for 32 minutes 10 seconds and deposits 0.325 g of M, What is the charge of the metal ion?
(M = 65, If = 96,500 C per mole of electron)
- A. 1
- B. 2
- C. 3
- D. 4
4.0 g of sodium hydroxide in 250 cm3 of solution contains?
- A. 0.40 moles per dm3
- B. 0.10 moles per dm3
- C. 0.04 moles per dm3
- D. 0.02 moles per dm3
NH3 + H3O+
→ NH4+ + H2O. It may be deduced from the reaction above that?
- A. a redox reaction has occurred
- B. H3O+ acts as an oxidizing agent
- C. H3O+ acts as an acid
- D. water acts as an acid
A student prepares 0.5 M solution each of hydrochloric and ethanoic acids and then measured pH. The result would show that the?
- A. pH values are equal
- B. HCI solution has a higher pH
- C. sum of the values is 14
- D. ethanoic acid solution has a higher pH
The phenomenon whereby sodium trioxocarbonate (IV) decahydrate loses some of its water of crystallization on exposure to the atmosphere is known as?
- A. deliquescene
- B. hygroscopy
- C. effervescence
- D. efflorescence
Water can be identified by the use of?
- A. anhydrous copper (II) tetraoxosulphate (VI)
- B. anhydrous sodium trioxocarbonate (IV)
- C. potassium heptaoxochromate (VII)
- D. copper (II) trioxocaronate (IV)
The air around a petroleum refinery is most likely to contain?
- A. CO2, SO3 and N2O
- B. CO2, CO and N2O
- C. SO2, CO and NO2
- D. PH3 H2O and CO2
Argon is used in gas-filled electric lamp because it helps to?
- A. prevent the reduction of the lamp fillaments
- B. prevent oxidation of the lamp fillaments
- C. make the lamp fillament glow brightly
- D. keep the atmosphere in the lamp inert
Water has a rather high boiling point despite its low molecular mass because of the presence of?
- A. hydrogen bonding
- B. covalent bonding
- C. ionic bonding
- D. metallic bonding
Which group of elements forms hydrides that are pyramidal in structure?
- A. III
- B. IV
- C. V
- D. VI