Study and practice Chemistry past questions with answers and detailed explanations. Then test your knowledge using our interactive CBT practice platform and prepare confidently for your upcoming examinations.
Athe removal of hydrogen from an alkane in the presence of a catalyst
Bthe addition of hydrogen to an alkane in the presence of a catalyst
Cthe addition of hydrogen to an alkyne
Dthe removal of hydrogen from an alkyne
Ethe addition of hydrogen to an ethyl alcohol
View Explanation & Discuss
Question 1213
jamb1979
The solution of a sample in a tube will be identified as a chloride if it gives
Aa white precipitate on addition of AgNO3 and barium chloride solutions
Ba white precipiate when acidified with HCI, and then AgNO3 solution added
Ca white precipitate when acidified with dilute HNO3 and then AgNO3 solution added
Da white precipitate when acidified with dilute H2SO4 and then barium nitrate solution added
Ea pungent smell of chlorine gas when dilute HCI and MnO2 are added
View Explanation & Discuss
Question 1214
jamb1979
The reaction 3C(s) + 2Fe2O3(s) = 4Fe(s) + 3CO2(g): \(\Delta\)H =46.0 kJ is
Aisothermic
Badiabatic
Cisobaric
Dendothermic
Eexothermic
View Explanation & Discuss
Question 1215
jamb1979
the vapour density of a gas may be defined as
Athe mass of a unit volume of the gas compared to an equal volume of water vapour
Bthe mass of a unit volume of the gas compared to an equal volume of hydrogen
Cthe mass of a unit volume of the gas compared to an equal volume of oxygen
Dthe mass of a unit volume of the gas minus the vapour pressure of water
Etwo times the relative molecular mass of the gas
View Explanation & Discuss
Question 1216
jamb1979
Which of the following statements is true?
Aan increase in the temperature of a given mass of gas increases the number of gas molecules
Ban increase in the temperature of the gas does not affect the kinetic energy
Can increase in the pressure of the gas is proportional to the increase in volume
Da increase in the pressure of a gas is proportional to the decrease in volume at constant temperature
Ea decrease in the pressure of the gas decreases the number of gas molecules present
View Explanation & Discuss
Question 1217
jamb1979
In the manufacture of iron in the blast furnace, iron (lll) oxide is mixed with coke and limestone, and different reactions occur in the process. Which of the following statements is true with respect to these reactions?
Athe coke is a powerful reducing agent and easily converts the iron oxide to iron
Bthe calcuim carbonate reacts with SiO2 an earthly impurity in the ore, to from calcuim silicate
Cthe coke will react with the iron produced to form steel
Dall the carbondioxide required in the process comes from the decomposition of the calcium carbonate
Ethe calcium carbonate decomposes to give calcium oxide, which then forms calcium silicate with the earthly impurity
View Explanation & Discuss
Question 1218
jamb1979
Weighed salts Y and Z were left exposed in the laboratory overnight. In the morning Y had gained weight, and Z had become liquid. What conclusion could be drawn about the nature of the two salts?
AZ is efflorescent
BY and Z are efflorescent
CY and Z are deliquescent
DY and Z are hygroscopic
EY is deliquescent
View Explanation & Discuss
Question 1219
jamb1979
The reaction between hydrogen and iodine may be represented by the equation H2(g)+ I2(g) → 2HI(g), and is exothermic. Therefore
Aan increase in temperature favours the forword reaction
Ban increase in pressure favours the backward reaction
Cboth pressure and temperature muct be increased to favour the forward reaction
Da decrease in temperature will favour the forward reaction
Ea decrease in pressure and an increase in temperature will favour the forward reaction
View Explanation & Discuss
Question 1220
jamb1979
Starch can be converted to ethyl alcohol by
Adistillation
Bfermentation
Cisomerization
Dcracking
Ecooking
View Explanation & Discuss
Question 1221
jamb1979
Calcium hydroxide and ammonium chloride when heated together will give an important product. This compound may be obtained dry by
Adissolving it in water, recrystallizing it and then drying in the oven
Bpassing it through a concentrated aqueous solution of sodium hydroxide
Cpassing it through calcium oxide
Dpassing it through concentrated sulphuric acid
Epassing it through anhydrous calcium choride
View Explanation & Discuss
Question 1222
jamb1979
In which of the following reactions is sulphur dioxide acting as an oxidizing agent?
ASO 2 + 2HNO3 →H2SO4 + NO2 + Heat
B2SO2 + 2H2O + O2→ 2H2SO4
CSO2 + 2H2O + CI2→ H2SO4 + 2HCI
DSO2 + 2H2S → 3S + 2H2O
ESO2 + H2O → H2SO3
View Explanation & Discuss
Question 1223
jamb1979
An anhydride is?
Aa compound wich has no water of crystallization
Ban oxide whose solution in water has a PH greater than 7
Can oxide whose solution in water has a PH less than 7
Dan oxide that has hydrogen atoms
Ean amphoteric oxide
View Explanation & Discuss
Question 1224
jamb1979
In the redox reaction\( 2Fe^{2+} + CI_2 → 2Fe^{3+} + 2Cl^-\)
ACl2 is reduced because it has lost electrons
BCl2 is reduced because its oxidation number has decreased
CCl2 is reduced because its molecule is change to two ions
DFe2+ is reduced because it has lost electrons
EFe2+ is reduced because it has gained electrons
View Explanation & Discuss
Question 1225
jamb1979
In the extraction of aluminum from purified bauxite by electrolysis, cryolite is used because
Ait makes bauxite a better conductor of electricity
Bit makes bauxite melt at a lower temperature
Cit makes aluminium purer
Dit prevents aluminium from getting oxidized
Eit protects the carbon electrodes used in the process
View Explanation & Discuss
Question 1226
jamb1979
Which one of these compounds will NOT give an oxygen gas on heating?
AManganese dioxide
BHydrogen peroxide
CZinc nitrate
DSodium nitrate
EAmmonium nitrate
View Explanation & Discuss
Question 1227
jamb1979
0.1 Faraday of electricity was passed through a solution of copper (ll) sulphate. The maximum weight of copper deposited on the cathode would be [Cu = 64]
A64.0g
B32.0g
C16.0g
D6.4 g
E3.2g
View Explanation & Discuss
Question 1228
jamb1979
Indicate which of the following statements is not true as we move from left to right along the periodic Table:
Aatomic number of elements increases
Batomic mass of elements increases
Celectropositive character of elements increases
Delectronegative character of elements increases
Enumber of electrons in the outermost orbits of element increases
View Explanation & Discuss
Question 1229
jamb1979
When a piece of charcoal enclosed in a cylinder containing air is ignited
Athe toatl volume of air is increased
Bthe relative amount of oxygen present is increased
Cthe relative amount of nitrogen present is decreased
Dthe relative amount of carbondioxide present is increased
Ethe ratio of oxygen to nitrogen in the system is increased
View Explanation & Discuss
Question 1230
jamb1979
The empirical formula of an oxide of nitrogen containing 30.4 per cent of nitrogen is (N=14.0,O=16.0)
