20 cm\(^3\) of hydrogen gas are sparked with 20cm\(^3\) of oxygen gas in an endimoeter at 373k (100\(^0\)C) and 1 atmosphere. The resulting mixture is cooled to 298 K (25 oC) and passed over calcium chloride. The volume of the residual gas is
Answer
(D)
10cm 3
3
For the reaction NH4NO2 \(\to\) N2 + 2H2O, calculate the volume of nitrogen that would be produced at S. T. P from 3.2 g of the dioxonitrate(iii)salt. (Relative atomic masses: N = 14, O = 16, H = 1)
Answer
(D)
1. 12dm 3
4
A molar solution of caustic soda is prepared by dissolving
Answer
(B)
40 g NaOH in 1000 g of water
5
Which among the elements 1. Carbon 2. Oxygen 3. Copper 4. Bromine 5. Zinc, will NOT react with either water or steam?
Answer
(B)
2 and 3
6
Naphthalene when heated melts at 354 K (81 oC). At this temperature the molecules of naphthalene
Answer
(E)
become mobile as the inter molecular forces are broken
7
The ratio of the number of molecules in 2g of hydrogen to that in 16g of oxygen is
Answer
(A)
2:1
8
The balanced equation for the reaction of tetraoxosulphate(VI)acid with aluminium hydroxide to give water and aluminium tetraoxosulphate(VI) is
Answer
(B)
3H2SO4 + 2Al(OH)3 \(\to\) 6H2O + Al2(SO4)3
9
Which of the following mixtures would result in a solution of pH greater than 7?
Answer
(A)
25.00 cm3 of 0.05 M H2SO4 and 25.00cm3 of 0.50 M Na2CO3
10
In which of the following reactions does hydrogen peroxide act as a reducing agent?
Answer
(D)
PbO2 + 2HNO3 + H2O2 \(\to\) Pb(NO3)2 + 2H2O + O2
11
For the reaction 2Fe3+ 2I- \(\to\) 2Fe2+ + I2, which of the following statements is TRUE?
Answer
(C)
I- is oxidized to I2
12
In dilute solution the heat of the reaction NaOH + HCl = NaCl + H2O is - 57.3kJ. Therefore the heat of the reaction 2NaOH + H2SO4 \(\to\) Na2SO4 + 2H2O is
Answer
(D)
- 114.6 KJ
13
Which of the following methods may be used to prepare trioxonitrate (V) acid (nitric acid) in the laboratory?
Answer
(C)
Heating sodium trioxonitrate (V) with tetraoxosulphate (VI) acid
14
Lime - water, which is used in the laboratory for the detection of carbon(iv)oxide is an aqueous solution of
Answer
(A)
Ca(OH)2
15
An element that can exist in two or more different structural forms which possess the same chemical properties is said to exhibit.
Answer
(E)
allotrophy
16
Sulphur
Answer
(C)
burns with a blue flame
17
Which of the following statements is NOT true of carbon monoxide?
Answer
(B)
CO is readily oxidized at room temperature by air to form CO2
18
From the reactions : ZnO + Na2O \(\to\) NaZnO and ZnO + CO2 \(\to\) ZnCO3 it may be concluded that zinc oxide is
Answer
(D)
amphoteric
19
An example of a neutral oxide is
Answer
(D)
CO
20
3Cl2 + 2NH3 \(\to\) N2 + 6HCl. In the above reaction, ammonia acts as
Answer
(A)
a reducing agent
21
In the Haber process for the manufacture of ammonia, finely divided iron is used as
Answer
(C)
a catalyst
22
The hybridization of the carbon atom in ethyne is
Answer
(D)
sp
23
An organic compound with a vapour density 56.5 has the following percentage composition:C =53.1% N = 12.4%, O = 28.3%, H = 6.2%. The molecular formula of the compound is
Relative atomic masses: N = 14, O = 16, C = 12, H = 1 )
Answer
(D)
C5H7O2N
24
When the kerosene fraction from petrol is heated at high temperature, a lower boiling liquid is obtained. This process is known as
Answer
(D)
cracking
25
Alkaline hydrolysis of naturally occurring fats and oils yields
Answer
(B)
soaps and glycerol
26
Which of the following statements is INCORRECT?
Answer
(E)
calcuim carbide will react with water to form any alkyne
27
Which of the following statements is NOT correct about all four of the acids: HBr, HNO3, H 2CO3 and H2SO4? They
Answer
(A)
dissolve marble to liberate CO
28
If the cost of electricity required to deposit 1 g of magnesium is N5.00, how much would it cost to deposit 10g of aluminium?
Answer
(D)
N66.67
29
Nitrogen can best be obtained from a mixture over oxygen and nitrogen by passing the mixture over
Answer
(D)
heated phosphorus
30
Water is said to be 'hard' if it
Answer
(C)
froms an insoluble scum with soap
31
Sodium hydroxide (NaOH) pellets are
Answer
(A)
deliquescent
32
Alkanes
Answer
(C)
contain only carbon and hydrogen
33
If an excess of a liquid hydrocarbon is poured into a jar of chlorine, and the sealed jar is then exposed for several hours to bring sunlight, all the chlorine gas is consumed. The hydrocarbon is said to have undergone
Answer
(D)
a substitution reaction
34
The function of conc. H2SO4 in the esterification of ethanoic acid with ethanol is to
Answer
(C)
act as a catalyst
35
A piece of sea shell, when dropped into a dilute solution of hydrochloric acid, produces a colourless, odourless gas which turns clear limewater milky. The sea shell contains
Answer
(C)
calcium carbonate
36
Which of the following electrodes is used in electrolysis of bauxite (Al2O3) in molten cryolite?
Answer
(B)
Carbon electrodes
37
An aqueous solution of a metal salt, M, gives a white precipitate with NaOH which dissolves in excess NaOH. With aqueous ammonia, the solution of M also gives a white precipitate which dissolves in excess ammonia. Therefore cartion in M is
Answer
(A)
Zn ++
38
At S. T. P how many litres of hydrogen can be obtained from the reaction of 500 cm\(^3\) of 0.5 M H\(_2\)SO\(_4\) with excess zinc metal?
(Gram molecular volume of H\(_2\) = 22.4 dm\(^3\))
Answer
(D)
5. 6 dm 3
39
The solubility curves of four substances are shown in the figure above. Which of the four substances would crystallize from a saturated solution cooled from 353K(80oC)to 323K(50C)?
Answer
(D)
R and S
40
Which of the curves shown in the figure given represents the relationships between the volume(V) and pressure(P) of an ideal gas at constant temperature
