The same current is passed for the same time through solutions of AgNO3 and CuSO4 connected in series. How much silver will be deposited if 1.0 g of copper is produced?
[Cu = 63.5, S = 32, O = 16, Ag = 108, N = 14]
- A. 1.7 g
- B. 3.4 g
- C. 6. 8 g
- D. 13. 6 g
An acid and its conjugate base
- A. can neutralise each other to form a salt
- B. differ only by a proton
- C. differ only by the opposite charges they carry
- D. are always neutral substances
The substance ZnO dissolves in sodium hydroxide solution and mineral acid solution to give soluble products in each case. ZnO is therefore referred to as
- A. an allotropic oxide
- B. an amphoteric oxide
- C. a peroxide
- D. a dioxide
A solution of calcium bromide contains 20 g dm 3 What is the molarity of the solution with respect to calcium bromide and bromide ions? [Ca = 40, Br = 80]
- A. 0. 1, 0 . 1
- B. 0. 1, 0. 2
- C. 0. 1, 0. 05
- D. 0.05, 0.1
Using 50 cm 3 of 1 M potassium hydroxide and 100cm 3 of 1 M tetraoxosulphate (VI) acid, calculate the respective volumes in cm 3 of base and acid that would be required to produce the maximum amount of potassium tetraoxosulphate (IV) [ = 39, S = 32, O = 16, H = 1]
- A. 50, 50
- B. 25, 50
- C. 50, 25
- D. 25, 25
A hydrated salt of formula MSO4.xH2 O CONTAINS 45.3% by mass of water of crystalisation. Calculate the value of x [M = 56, S = 32, O = 16, H = 1 ]
- A. 3
- B. 5
- C. 7
- D. 10
Calcium hydroxide is added in the treatment of town water supply to
- A. kill bacteria in the water
- B. facilitate coagulation of organic particles
- C. facilitate sedimentation
- D. improve the taste of the water
The gaseous pollutant sulphur (IV)oxide is most likely to be detected in fairly reasonable quantities in the area around a plant for the
- A. extraction of aluminium from bauxite
- B. production of margarine
- C. smelting of copper
- D. production of chlorine from brine
How many valence electrons are contained in the element represented 3115P?
- A. 3
- B. 5
- C. 15
- D. 31
Four elements P,Q, R and S have atomic numbers of 4, 10, 12 and 14 respectively . Which of these electrons is a noble gas?
- A. P
- B. Q
- C. R
- D. S
The atomic number of caesium is 55 and its atomic mass is 133. The nucleus of caesium atom therefore contains
- A. 78 protons and 55 elections
- B. 55 protons and 78 neutrons
- C. 55 neutrons 78 electrons
- D. 78 protons and 55 neutrons
Elements X and Y have electronic configurations 1s\(^2\)2s\(^2\)2p\(^4\) and 1s\(^2\)2s\(^2\)2p\(^6\)3s\(^2\)3p\(^1\) respectively. When they combine, the formula of the compound formed is?
- A. XY
- B. YX
- C. X2Y3
- D. Y2X3
The atomic radius of Li, Na and K are 1: 33A, 1. 54A and 1. 96A res pectively. Which of the following explaqins this gradation in atomic radius?
- A. electropositivity decreases from Li to Na to K
- B. electronegativity decreases from Li to Na to K
- C. the number of the electron shells increases from Li to Na to K
- D. the elements are in the same period
What is the partial pressure of hydrogen gas collected
over water at standard atmospheric pressure and 25 oC if the saturation vapour pressure of water at saturation vapour pressure of water is 23 mm Hg at that temperature?
- A. 737 mm Hg
- B. 763 mm Hg
- C. 777 mm Hg
- D. 783 mm Hg
The minimum volume of oxygen required for the complete combustion of a mixture of 10cm 3 of CO and 15 cm 3 of H 2 is
- A. 25.0cm3
- B. 12.5 cm3
- C. 10.0 cm3
- D. 5.0cm3
20.00 cm 3 of a solution containing 0.53 g of anhydrous Na2CO3 in 100 cm3 requires 25.00 cm3 of H2SO4 for complete neutralisation. The concentration of the acid solution in moles per dm is [H =1, C = 12, O = 16, Na =23, S = 32]
- A. 0.02
- B. 0.04
- C. 0.06
- D. 0.08
The molar ratio of carbon to hydrogen of a volatile liquid compound is 1: 2. 0. 12 g of the liquid on evaporation at s.t.p. gave 32 cm3 of vapour. The molecular formula of the liquid is
[G.M.V =22.4 dm 3, C = 12, H = 1]
- A. C 3 H 6
- B. C 4H 8
- C. C 5C 10
- D. C 6H 12
Which of the following would support the conclusion that a solid sample is a mixture?
- A. the solid can be ground to a fine powder
- B. the density of the solid is 2.25 g dm3
- C. the solid has a melting range of 300oC to 375oC
- D. the solid absorbs moisture from the atmosphere
Consider the following exothermic reaction \(2SO_{2(g)} + O_{2(g)} = 2SO_{3(g)}\) . If the temperature of the reaction is reduced from 800ºC to 500ºC, and no other change takes place, then
- A. the reaction rate increases
- B. concentration of SO3 decreases
- C. concentration of SO3 increases
- D. SO2 gas becomes unreactive
- E. O2 gas becomes unreactive
Pick out the correct statement
- A. Zin heated to redness reacts with steam to give oxygen and zinc oxide
- B. Zinc heated to redness reacts with steam to give oxygen and hydrogen
- C. Zinc does not react with hot or cold water
- D. Zinc reacts with hot water to form zinc oxide and hydrogen
- E. Zinc reacts very easily with cold water to give zinc oxide and hydrogen
A piece of metal (M) is dissolved in nitric acid and the resulting solution is treated with a small quantity of sodium hydroxide to produce a white precipitate (B) which redissolves on the addition of excess alkali. The precipitate (B)when ignited in a crucible produces the oxide of the metal(m). The METAL M is
- A. Zn
- B. Cu
- C. Al
- D. Au
- E. Ca