Jamb repeated questions in chemistry (1 to 10)

1. Unsaturated organic compounds can be identified by the decolourization of Bromine water and potassium per manganate.
2. Tetrachloromethane is a chlorinated .
3. The alkane homologous series is given by C_{n}H_{2n+2}. Also NOTE that each consecutive member of this homologous series differs by a CH_{2} group
4. The three-dimensional shape of methane molecule is tetrahedral
5. A compound with a Sweet smelling smell like that of fruits is an ester also known as alkanoate.
6. The organic compound C_{3}H_{6}Br_{2} has 4 isomers and the isomers are:
   • 1,1-dibromo-propane
   • 1,2-dibromopropane
   • 2,2-dibromopropane
   • 1,3-dibromopropane
7. The organic compound C_{4}H_{10} has 2 isomers and the isomers are:
   • n-butane
   • 2-methylpropane also known as isobutane
8. The organic compound C_{5}H_{12}(pentane) has 3 isomers and the isomers are:
   • n-pentane
   • 2-methylbutane
   • 2,2-dimethypropane
9. The organic compound C_{6}H_{14} has 5 isomers and the isomers are:
   • n-hexane
   • 2-methylpentane
   • 3-methylpentane
   • 2,2-dimethylbutane
   • 2,3-dimethylbutane
10. The Cracking process is important in the petroleum industries because it helps to yield more engine fuels

Jamb repeated questions in chemistry (11 to 20)

1. 1. The process of obtaining compound with lower boiling points from compounds with higher boiling and melting point is termed cracking
   2. Alkaline hydrolysis of naturally occuring fat and oils yield soap and glycerol
   3. The Carboxylic acid also known as the alkanoic acid is represented by RCOOH
   4. The Esters also known as alkanoates can be representd by RCOOR’
   5. In esterification of ethanol and ethanoic acid, the Conc.H_{2}SO_{4} used in the reaction acts as a Dehydrating agent
   6. Complete hydrogenation of ethyne will yield ethane
   7. Complete oxidation of alcohol will yield carboxylic acid also knnown as alkanoic acid.
   8. When alcohol vapor is passed through a solution of potassium dichromate a colour change from orange to green occurs
   9. Ammoniacal silver nitrate solution can be used to distinguish Alkenes from Alkynes
   10. Thr process of converting oils to magarine or solid fat is termed HYDROGENATION

Likely Jamb questions and answers in chemistry (21-30)

1. 1. The salt (sodium chloride) present in the saponification process helps to separate out the soap from the glycerol
   2. The organic compound C_{3}H_{8}O has 3 isomers which are:
      • 1-propanol
      • 2-propanol
      • methoxyethane
   3. When ethanol is heated in excess conc tetraoxosulphate vi acid, the ethanol is dehydrated to ethene gas
   4. Alkanoic acid react with trioxocarbonate salts with the evolution of carbon(iv)oxide gas(i.e effervescence occurs during reaction of alkanoic acid with a trioxocarbonate salt Na_{2}CO_{3}
   5. Lead tetra-ethyl is used as anti-knock in petrol engines
   6. The reaction that occurs when Palm-oil is added to potash is with the formation of foam is termed Saponification
   7. Starch is converted to Ethyl alcohol by the process called Fermentation
   8. The efficiency of petrol as fuel in high compression internal combustion will increase in the presence of increased branch chain alkanes
   9. The fuction of the ash in the locally made black soup is to supply the alkali necessary for saponification to take place.
   10. Water added to calcium carbide in a container produces a gas called acetylene

Likely Jamb Chemistry questions and answers31-40)

1. 1. Detergent have the following general formula RSO_{3}Na^{+}
   2. When excess Chlorine is mixed with ethene an organic compound with the name 1,2-dichloroethane is produced
   3. The bond which joins two ethanoic acid molecule in its liquid state is the Hydrogen bond. Note that this hydrogen bond also joins two molecules of ethanol together.
   4. The gas responsible for the fatal explosion in the coal mines is the methane gas
   5. cycloalkane with the formula C_{5}H_{10} has
   6. Alkanals can be differentiated from alkanones by their reaction with Tollen’s reagent
   7. glucose and cellulose are examples of polysachharide.
   8. The carbon atoms in the alkane homologue are sp3 hybridized
   9. The carbon atoms in the alkene homologue are Sp2 hybridized
   10. The carbon atoms in the alkyne homologue are Sp hybridized

Jamb repeated questions and likely questions and answers in chemistry)

1. The presence of copper sulphate solution in tetraoxosulphate(vi) acid in the preparation of acetylene gas it to remove the phosphine impurity produce.
2. Bromine water will confirm the presence of unsaturation in an organic compound
3. When sodium is added to ethanol the compound produced is Sodium ethoxide while hydrogen gas is also liberated
4. The general formula for alkanals or aldehydes is RCHO
5. The general formula for alkanones or ketones is RCOR’ or R_{2}CO.
6. The general formula for ether or alkyoxide is R-O-R
7. The relative high boiling points of alcohols is due to the presence of hydrogen bond
8. The products obtained when hydrocarbon is burned in the presence of excess air is water vapour and carbon(iv)oxide
9. Sulphur is used for the vulcanization of rubber
10. Ethanol is used as a solvent in perfume